Preventing Enemy Coalitions Preventing Enemy Timothy W

Preventing Enemy Coalitions Preventing Enemy Timothy W. Crawford Coalitions How Wedge Strategies Shape Power Politics

How do states dissuade adversaries from organizing against them? When do they succeed in splitting opponents that have formed or are likely to form an alliance? How do such “wedge strategies” inºuence larger patterns of international politics? Scholars have focused much attention on how alliances form and whether they are driven by balancing, bandwagoning, or other dynamics.1 They have paid less attention to the role of wedge strategies in disrupting or preventing the formation of alliances and to understanding how and when those strategies succeed.2

Timothy W. Crawford is Associate Professor of Political Science at Boston College.

For helpful comments and discussion on earlier drafts, the author would like to thank Jonathan Caverley, Michael Glosny, Stacie Goddard, Yasuhiro Izumikawa, Ronald Krebs, Orly Mishan, T.V. Paul, Evan Resnick, Norrin Ripsman, Robert Ross, Jack Snyder, Karen Yarhi-Milo, and the anony- mous reviewers. He would also like to thank participants in conference panels at meetings of the American Political Science Association and International Studies Association, as well as seminar participants at Harvard University’s John M. Olin Institute for Strategic Studies and the Massa- chusetts Institute of Technology’s Security Studies Program, for their comments and suggestions. The following Boston College undergraduate and graduate research assistants also deserve thanks: Raakhi Agrawal, Danielle Cardona, Jonathan Culp, Alexandre Provencher-Gravel, and Amanda Rothschild.

1. Kenneth N. Waltz, Theory of International Politics (New York: Random House, 1979); Stephen M. Walt, The Origins of Alliances (Ithaca, N.Y.: Cornell University Press, 1987); Paul Schroeder, “Histor- ical Reality versus Neo-realist Theory,” International Security, Vol. 19, No. 1 (Summer 1994), pp. 108–148; Thomas J. Christensen and Jack Snyder, “Chain Gangs and Passed Bucks: Predicting Alliance Patterns in Multipolarity,” International Organization, Vol. 44, No. 2 (Spring 1990), pp. 137– 168; Randall L. Schweller, Deadly Imbalances: Tripolarity and Hitler’s Strategy of World Conquest (New York: Columbia University Press, 1998); John J. Mearsheimer, The Tragedy of Great Power Politics (New York: W.W. Norton, 2001); John A. Vasquez and Colin Elman, eds., Realism and the Balancing of Power: A New Debate (Upper Saddle River, N.J.: Prentice Hall, 2003); and T.V. Paul, James J. Wirtz, and Michel Fortmann, eds., Balance of Power: Theory and Practice in the 21st Century (Palo Alto, Ca- lif.: Stanford University Press, 2004). 2. For an initial effort by this author, see Timothy W. Crawford, “Wedge Strategy, Balancing, and the Deviant Case of Spain, 1940–41,” Security Studies, Vol. 17, No. 1 (Winter 2008), pp. 1–38. Other important recent studies include Yasuhiro Izumikawa, “United We Stand, Divided They Fall: Use of Coercion and Rewards as Alliance Balancing Strategy,” Ph.D. dissertation, Georgetown Univer- sity, 2002; Victoria Tin-bor Hui, War and State Formation in Ancient China and Early Modern Europe (Cambridge: Cambridge University Press, 2005); Stacie E. Goddard, “When Right Makes Might: How Prussia Overturned the European Balance of Power,” International Security, Vol. 33, No. 3 (Winter 2008/09), pp. 110–142; Daniel H. Nexon, The Struggle for Power in Early Modern Europe: Re- ligious Conºict, Dynastic Empires, and International Change (Princeton, N.J.: Princeton University Press, 2009); and Michael Glosny, “The Grand Strategies of Rising Powers: Reassurance, Coercion, and Balancing Responses,” Ph.D. dissertation, Massachusetts Institute of Technology, 2011. Key discussions are also found in Daniel H. Nexon, “The Balance of Power in the Balance,” World Poli-

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I deªne a “wedge strategy” as a state’s attempt to prevent, break up, or weaken a threatening or blocking alliance at an acceptable cost. When the strategy is successful, the state (i.e., the divider) gains advantage by reducing the number and strength of enemies organized against it. Because wedge strategies can turn opponents into neutrals or allies, they can trigger surprising power shifts with signiªcant consequences for war and peace and the trajec- tory of international politics. Adolf Hitler’s diplomatic coup of August 1939— the Nazi-Soviet nonaggression pact—dismantled the only counterbalancing coalition that could have derailed German aggression against Poland.3 On the other side of Eurasia, the Soviet Union secured Japanese neutrality in an April 1941 pact that held until August 1945, when the Soviet Union invaded Japanese-occupied Manchuria. The pact drove a wedge into the Axis alliance and was a boon to Soviet security after Germany’s invasion. In particular, Japan’s continued neutrality in late 1941 and early 1942 allowed massive transfers of Soviet military power from the Far East to the western front.4 Knowing

tics, Vol. 61, No. 2 (April 2009), pp. 340–347; Norrin M. Ripsman and Jack S. Levy, “Wishful Thinking or Buying Time? The Logic of British Appeasement in the 1930s,” International Security, Vol. 33, No. 2 (Fall 2008), pp. 148–181; Daniel Byman and Matthew Waxman, The Dynamics of Coer- cion: American Foreign Policy and the Limits of Military Might (New York: Cambridge University Press, 2002), pp. 171–172; Stuart J. Kaufman, Richard Little, and William C. Wohlforth, eds., The Balance of Power in World History (Basingstoke, U.K.: Palgrave Macmillan, 2007); Schweller, Deadly Imbalances, pp. 77–78; Robert Jervis, System Effects: Complexity in Political and Social Life (Princeton, N.J.: Princeton University Press, 1997), pp. 188–191; Glenn H. Snyder, Alliance Politics (Ithaca, N.Y.: Cornell University Press, 1997), pp. 337–338; Richard Rosecrance and Chih-Cheng Lo, “Balancing, Stability, and War: The Mysterious Case of the Napoleonic International System,” International Studies Quarterly, Vol. 40, No. 4 (December 1996), pp. 479–500; Frederick H. Hartmann, The Rela- tions of Nations, 5th ed. (New York: Macmillan, 1978), pp. 333–337; George Liska, Nations in Alli- ance: The Limits of Interdependence (Baltimore, Md.: Johns Hopkins University Press, 1968), pp. 42– 60; and Ivo D. Duchacek, Conºict and Cooperation among Nations (New York: Holt Rinehart, 1960), pp. 372–377. See also Hans J. Morgenthau, Politics among Nations: The Struggle for Power and Peace (New York: Alfred A. Knopf, 1948), p. 134; George Modelski, A Theory of Foreign Policy (New York: Praeger, 1962), p. 132; A.F.K. Organski, World Politics, 2d ed. (New York: Alfred A. Knopf, 1968), pp. 278–279; and Waltz, Theory of International Politics, p. 118. For cross-disciplinary insights, see Eric A. Posner, Kathryn E. Spier, and Adrian Vermeule, “Divide and Conquer,” Olin Working Pa- per, No. 467 (Chicago: University of Chicago Law and Economics, May 26, 2009), http://ssrn.com/ abstractϭ1414319. 3. I discuss this case at length below. 4. See Boris Slavinsky, The Japanese-Soviet Neutrality Pact: A Diplomatic History, 1941–1945, trans. Geoffrey Jukes (New York: Routledge, 2004); and George A. Lensen, The Strange Neutrality: Soviet- Japanese Relations during the Second World War, 1941–1945 (Tallahassee: Diplomatic Press, 1974). “It is possible,” wrote Paul W. Schroeder, “that Russia was saved [in 1941] because Japan persisted in her refusal to launch an attack upon Siberia.” Schroeder, The Axis Alliance and Japanese-American Relations, 1941 (Ithaca, N.Y.: Cornell University Press, 1958), p. 166; see also p. 48. The Soviet redeployments from the Far East “played a vital role in the war in the west [and had] a signiªcant role in halting German forces on the approaches to Moscow and in launching the Red Army’s en-

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more about when wedge strategies work and why can help scholars better explain such intrinsically important historical contingencies as these. There are ªve other main reasons why it is useful to understand how wedge strategies work and when they are likely to succeed. First, leaders can use this information to craft policies designed to divide their adversaries or to defend their own states’ alliances. In particular, conceptual models of wedge strategies can help to frame options to divide potential adversaries in real-world scenarios. They can also highlight critical variables and favorable conditions, as well as the chances of success or failure.5 Second, understanding how and when wedge strategies work can illuminate a principal cause of war: states’ disagreements about relative power.6 A major source of such disagreements is differing expectations about who will ally with whom and who will decide to be neutral when conºict turns violent. Wedge strategies foster these kinds of disagreements and the uncertainties that underpin them. Third, knowing more about how wedge strategies work can strengthen scholars’ grasp of the substance of states’ external balancing behavior and thus contribute to more accurate theories of balancing.7 As substitutes to arms and alliance building, wedge strategies are among the options available to states seeking to balance against threats. A fuller understanding of wedge strategies can therefore help scholars better assess the presence of balancing behavior in speciªc cases, as well as the prevalence of balancing in international politics more broadly. Fourth, knowing how and when wedge strategies work can enable scholars

suing counteroffensive.” David M. Glantz, The Soviet Strategic Offensive in Manchuria, 1945: “Au- gust Storm” (London: Frank Cass, 2003), pp. 5–6; for details of the transfers, see pp. 43–44 n. 11. 5. See Alexander L. George, Bridging the Gap: Theory and Practice in Foreign Policy (Washington, D.C.: United States Institute of Peace Press, 1993), chap. 10. 6. See Geoffrey Blainey, The Causes of War, 3d ed. (New York: Free Press, 1988), pp. 108–127; James D. Fearon, “Rationalist Explanations for War,” International Organization, Vol. 49, No. 3 (Summer 1995), pp. 392–393; and Jack S. Levy and William R. Thompson, Causes of War (Chichester, U.K.: Wiley-Blackwell, 2010), pp. 64–65. 7. Norrin M. Ripsman and Jack S. Levy have stressed the need for “more attention to the various sub-strategies and combinations of them, through which states pursue a larger strategy of balancing.” Ripsman and Levy, “The Preventive War That Never Happened: Britain, France, and the Rise of Germany in the 1930s,” Security Studies, Vol. 16, No. 1 (January–March 2007), p. 66. On the importance of enriching “theories of balancing,” see also Nexon, “The Balance of Power in the Bal- ance”; Christopher Layne, “The Unipolar Illusion Revisited: The Coming End of the United States’ Unipolar Moment,” International Security, Vol. 31, No. 2 (Fall 2006), pp. 28–29; and Glenn H. Snyder, “Process Variables in Neorealist Theory,” in Benjamin Frankel, ed., Realism: Restatements and Renewal (London: Frank Cass, 1996), pp. 167–192, especially p. 186.

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to explain why external balancing sometimes fails to check expansionists in circumstances where counterbalancing is expected to work—a puzzle of con- siderable importance to realist research programs.8 Fifth, understanding wedge strategy dynamics helps to address the broader theoretical and practical question raised by balancing failures: Is balancing a robust and common dynamic in international politics, or is it a subordinate and sporadic one? This article makes three main claims about the success of wedge strategies against adversaries with a strong propensity to ally or remain allied. First, wedge strategies that “selectively accommodate” one adversary (i.e., a target) while standing ªrm against other adversaries are more likely to divide an opposing coalition than strategies that rely on confrontation and coercion. Sec- ond, selective accommodation is most effective in promoting neutral alignment outcomes, that is, in inducing targets to become or remain neutral. Third, selective accommodation works best when dividers manipulate secondary interests (e.g., assets in peripheral areas, existing alliance ties, economic relationships, and market positions) that beneªt targets in ways that are important to the targets, yet are largely under the dividers’ control. That these wedge strategies can disrupt or prevent the formation of threatening or blocking alliances has important implications for theory and for the analysis of power politics. Brieºy, they pertain to the nature of external balancing, on the one hand, and the sources of balancing failure, on the other. First, defensive “divide-and-balance” wedge strategies are an important tool in a state’s portfolio of responses to threat, particularly when the state is facing a likely or an actual coalition of challengers. Such strategies seek to isolate the main threat by neutralizing lesser ones or at least degrading their level of cooperation. When assessing balancing behavior, scholars may be less likely to observe this form of external balancing than they are arms and alliance building. The political gains from divide-and-balance wedge strategies can be as signiªcant, however, because breaking or degrading an expansionist’s alliances can reduce its relative power, curtail its ambitions, and deter it from using force to pursue them. Second, expansionists can use offensive wedge strategies to break up anticipated or actual counterbalancing alliances, and thus promote balancing failures. Here, the divider attempts to reduce the size of the blocking coalition by offering to compensate a state that would otherwise suffer from the destruc-

8. See Vasquez and Elman, Realism and the Balancing of Power.

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tion of the status quo, and thus rally to defend it. This article shows how offensive wedge strategies can be a primary, antecedent cause of the antibalancing behaviors that many scholars think of as independent pathologies (e.g., buck- passing, distancing, and hiding). In addition, it argues that effective offensive wedge strategies are best understood as costly, anticipatory responses to the strength of the balancing dynamic in international politics, not evidence of its weakness. This article has two main sections. In the ªrst section, I develop the concepts and deductive arguments that identify successful wedge strategies and the conditions for their success. I begin with a discussion of selective accommodation and its alternative—confrontation—and explain why selective accommodation is more useful in dealing with cohesive and dangerous adversaries. Next, I survey the alignment goals that dividers seek and show why wedge strategies that promote neutral alignment outcomes have the best prospects for success and strategic impact. I then describe the inducements that dividers can offer when attempting to selectively accommodate a target, and explain why inducements based on secondary (as opposed to primary or tertiary) interests tend to work best. In the second main section, I discuss the larger implications of my argument for power politics more generally. I consider the key implications of wedge strategies for external balancing and balancing failure, and demonstrate their usefulness in understanding two cases in the lead-up to World War II. I close with some additional thoughts on how wedge strategies work and why scholars should give them greater scrutiny when studying balance of power politics.

How and When Do Wedge Strategies Work?

States use wedge strategies to inºuence other states’ alignments by manipulat- ing promises and threats, rewards and punishments. States can use them in two kinds of circumstances: reinforcing wedge strategies encourage targets to do what they are probably already going to do; countervailing wedge strategies encourage targets to do what they probably would not otherwise do.9 Dis- tinguishing between the two situations is essential to understanding how and when wedge strategies work, and it has implications for the type of inºuence dividers tend to use. Countervailing attempts succeed less often than reinforc-

9. See David A. Baldwin, “Power Analysis and World Politics: New Trends versus Old Ten- dencies,” World Politics, Vol. 31, No. 2 (January 1979), pp. 162–163.

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ing attempts, but they matter more when they achieve their objectives:10 they disperse and decrease the amount of power that would otherwise be organized against the divider. They can also incite miscalculation and surprise, as the “startling” Nazi-Soviet pact did in August 1939, when its announcement “astounded the world.”11 Assessing the effects of successful countervailing wedge strategies in speciªc cases thus means wrestling with big counterfactual historical questions about the alignment relations that would have otherwise occurred or been likely to occur, and about the strategic importance of the con- tingent chain of events that would have followed.

selective accommodation versus confrontation There are two broad approaches to dividing adversaries: selective accommodation and confrontation.12 Here I focus on selective accommodation strategies because dividers tend to use them when they seek countervailing effects, that is, when it matters most and can make the biggest difference. logics of division. Selective accommodation strategies mix carrots and sticks to create divergent pressures on members or potential members of an opposing alliance.13 This logic was at the root of a French diplomat’s worry in 1938 that the Italian dictator Benito Mussolini would “drive a wedge” between Britain and France by “blowing cold on France and hot on England.”14

10. Although in relation to different questions, botched reinforcing attempts are also interesting, especially those that perversely strengthen ties between fractious parties. 11. Schroeder, The Axis Alliance and Japanese-American Relations, 1941, p. 112; Norman Rich, Hitler’s War Aims, Vol. 2: The Establishment of the New Order (London: Andre Deutsch, 1973), p. 68. See also Michael I. Handel, The Diplomacy of Surprise: Hitler, Nixon, Sadat (Cambridge, Mass.: Harvard Cen- ter for International Affairs, 1981), chap. 3. 12. In principle, wedge drivers could rely exclusively on either carrots or sticks. Snyder, Alliance Politics, p. 338. In practice, the key distinction is between dividers that mix carrots and sticks to discriminate among adversaries, and those that consistently confront them. Izumikawa, “United We Stand, Divided They Fall,” p. 3. 13. I use the term “accommodation” instead of other possibilities, such as “incentives,” because it has a conventional meaning in the statecraft literature essential to this subject. Accommodation is an act that a state undertakes for the beneªt of an actual or potential adversary. It denotes the making of concessions, or the taking of steps that compensate or credit the adversary’s interests, for the sake of improving relations or sidestepping conºict. See Arnold Wolfers, “Peace Strategies of De- terrence and Accommodation,” in Wolfers, ed., Discord and Collaboration: Essays on International Politics (Baltimore, Md.: Johns Hopkins University Press, 1962), chap. 9; Glenn H. Snyder and Paul Diesing, Conºict among Nations: Bargaining, Decision Making, and System Structure in International Crises (Princeton, N.J.: Princeton University Press, 1977), p. 243; and Alexander L. George, Forceful Persuasion: Coercive Diplomacy as an Alternative to War (Washington, D.C.: United States Institute of Peace Press, 1991), pp. 73–75. The term “selective incentives” is used in a similar sense by Kaufman, Little, and Wohlforth, Balance of Power in World History. See also Rosecrance and Lo’s ref- erences to “side payments,” “seductive blandishments,” and “territorial plums.” Rosecrance and Lo, “Balancing, Stability, and War,” pp. 487, 491, 496. 14. British ambassador to France, quoted in Documents on British Foreign Policy [hereafter DBFP],

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It is also the logic behind Frederick Hartmann’s “cardinal principle” of the “conservation of enemies,” which prescribes “deliberately holding down the opponent’s number of allies by making policy adjustments that satisfy the requirements of third nations.”15 A divider employing a selective accommodation strategy uses concessions and other inducements to lure a target away from other adversaries, which are dealt with more ªrmly. In countervailing situations, the approach is likely to produce positive results under three conditions. First, the inducements beneªt the target in issue areas it considers of major importance. Second, the divider has prevailing inºuence, if not exclusive control, over the target’s access to those beneªts. Third, the target’s allies (or potential allies) cannot easily provide substitutes to the divider’s inducements or outbid them.16 Selective accommodation can weaken the cohesion of an adversary in several ways. First, inducements can encourage the target to separate or keep its distance from other members of an opposing coalition. Second, rewards can create new, or aggravate existing, conºicts between the target and its allies (or potential allies). Third, insofar as the adversaries share a view of the divider as a potential enemy, selective accommodation can weaken their common threat perception. For this reason, for example, Western strategists worried more about Soviet “peace offensives” eroding NATO cohesion and collective security efforts than about the alliance crumbling under Soviet bullying.17 Instead of blowing hot in one direction and cold in another, confrontational wedge strategies blow cold against all comers. The basic idea behind this strategy is that consistent toughness and intimidation will expose and exacerbate gaps in the adversaries’ strategic interests, increasingly strain their ability to cooperate, and precipitate defections.18 Underlying this idea is the belief that

3d ser., Vol. 3 (London: Her Majesty’s Stationery Ofªce, 1953), p. 257. The “pressure” wedge strategy that Dwight Eisenhower’s administration used to try to fracture the Sino-Soviet alliance high- lights this pattern. The strategy, in Lorenz M. Lüthi’s words, coupled “confrontation toward the PRC and moderation toward the USSR.” See John Lewis Gaddis, “The American ‘Wedge’ Strategy, 1949–1955,” in Harry Harding and Yuan Ming, eds., Sino American Relations, 1945–1955: A Joint Re- assessment of a Critical Decade (Wilmington, Del.: Scholarly Resources, 1989), pp. 167–172; and Lüthi, The Sino-Soviet Split: Cold War in the Communist World (Princeton, N.J.: Princeton University Press, 2008), p. 247. 15. Frederick H. Hartmann, The Conservation of Enemies: A Study in Enmity (Westport, Conn.: Greenwood, 1982), p. 147. See also Schweller, Deadly Imbalances, p. 75. 16. For related discussion, see Izumikawa, “United We Stand, Divided They Fall,” pp. 15–17. 17. See Kenneth Osgood, “The Perils of Coexistence: Peace and Propaganda in Eisenhower’s For- eign Policy,” in Klaus Larres and Osgood, eds., The Cold War after Stalin’s Death: A Missed Opportu- nity for Peace? (Lanham, Md.: Rowman and Littleªeld, 2006), chap. 2. On the 1955 Soviet peace offensive toward Japan, see Izumikawa, “United We Stand, Divided They Fall,” chap. 7. 18. This logic clearly translates into concepts of coercive diplomacy. See Byman and Waxman, The

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at least one of the potential adversaries is a weak link that, under the stress of confrontation, will be deterred from joining a hostile alliance or be dislodged from it.19 The perceived vulnerabilities that invite such attempts may reºect basic differences in the geographical position, strategic priorities, relative capabilities, or ideological claims and pretensions of the members of an opposing alliance. Whatever the source, the divider wagers that confrontation will reinforce disintegrative tendencies and disperse the adversaries.20 logics of choice. Whether a divider uses selective accommodation or confrontation is inºuenced by its perception of the risks of balancing blowback, that is, the risk that its approach will unite rather than divide its adversaries. The higher the risk of blowback, the more sense it makes to use selective accommodation and avoid confrontation. A divider must consider two factors when assessing the risk of blowback: the apparent strength of the adversaries’ cohesion and the danger posed by their acting in concert. Dividers that misjudge the signiªcance of these factors may provoke blowback and self- encirclement and thus wind up challenged by a stronger, rather than weaker, opposing alliance. The likelihood of blowback is greater in countervailing situations than in reinforcing ones. When a divider believes that its adversaries’ propensity to ally against it is strong, the divider should prefer to use a selective accommodation strategy, assuming the option is available and the costs are acceptable. Selec- tive accommodation can erode the bases of their alignment and minimize the risk of blowback.21 The gravity of the combined threat, however, also matters. The more the adversaries’ organized power endangers the divider’s position and goals, the more the divider will seek to avoid blowback. Thus, when the

Dynamics of Coercion, pp. 171–172. The idea of a confrontational wedge strategy, however, should not be stretched to include the military imposition of a “separate peace” on a belligerent member of a hostile alliance. Thus, the Entente’s policies to induce Italy to remain neutral in 1914, and then to attack Austria–Hungary in 1915, were wedge strategies. The Allies’ forcing Italy to surrender and abandon Germany in 1943 was not. 19. German policy in the 1914 July Crisis reºected, at least partly, such calculations, with the challenge to Russia’s protégé Serbia leading to a breakup of the Entente. According to Kurt Riezler’s diary, Chancellor Bethmann Hollweg believed that Germany’s hard line in the July Crisis offered “the prospect of splitting the entente ...iftheTsarisunwilling [to defend Serbia] or France, alarmed, counsels peace.” Quoted in Konrad H. Jarausch, “The Illusion of Limited War: Chancel- lor Bethmann Hollweg’s Calculated Risk, July 1914,” Central European History, Vol. 2, No. 1 (March 1969), p. 58. See also Fritz Fischer, Germany’s Aims in the First World War (New York: W.W. Norton, 1961), p. 60. 20. Thus, as some analysts said of the Sino-Soviet alliance, powers bound by a dogmatic revolu- tionary ideology are vulnerable to coercive pressures that raise the stakes of their internecine ªghts over the movement’s leadership and doctrinal orthodoxy. Walt, The Origins of Alliances, pp. 35–37. 21. Izumikawa, “United We Stand, Divided They Fall,” pp. 14–17.

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likelihood and danger that adversaries will unite are high, dividers will prefer to use selective accommodation wedge strategies. When the perceived risks of blowback are low—either because members of the opposing coalition do not appear cohesive or dangerous in combination—the divider is more likely to try confrontation.22 These broad propositions provide useful insights into why states attempt different wedge strategies, and when and how they work. They help to clarify why dividers try to accommodate some adversaries that seem likely to join or remain in dangerous alliances.23 They also help to explain why states might try to divide adversaries by confronting them, despite the risk of driving them together.24 Thus, a divider believing that it is much stronger than a group of weaker adversaries may employ a confrontational approach, calculating that it will impel them to bandwagon (as weak states tend to do when they lack great power supporters).25 Even though the divider has rewards to parlay, the lower danger and likelihood of balancing blowback leads it to opt for confrontation instead: threats are cheaper than inducements when they work, and in this scenario, they are likely to prove effective.26 Still, some states opt for confrontation even when they face a strong and cohesive alliance. Yasuhiro Izumikawa identiªes two key conditions of scarcity that together can lead a state to choose confrontation under such less-than- propitious circumstances. First, the state does not have the resources or “re-

22. This does not mean that confrontation will be likely. If the goal is to divide, selective accommodation is still a preferable approach, even when the situation gives more leeway for a coercive approach. When the danger and likelihood of adversaries combining their capabilities are perceived to be very low, the state should prefer to do nothing, unless the adversaries are so powerful that it must conciliate one to balance against the other. On this latter contingency, see Daniel Treisman, “Rational Appeasement,” International Organization, Vol. 58, No. 2 (Spring 2004), pp. 345–373. 23. This thinking runs counter to the “conºict expectations” model, which would posit that dividers will prefer to use coercion against adversaries they think are likely to unite and remain hostile, and save inducements for parties with whom they are and expect to remain friendly. See Daniel W. Drezner, “The Trouble with Carrots: Transaction Costs, Conºict Expectations, and Economic In- ducements,” Security Studies, Vol. 9, Nos. 1–2 (Autumn 1999), pp. 188–218. 24. Izumikawa, “United We Stand, Divided They Fall,” is the ªrst to raise and address this issue systematically, but see also Snyder, Alliance Politics; and Rosecrance and Lo, “Balancing, Stability, and War.” A state may also opt for confrontation because it does not want to divide its adversaries. For example, it may not want to allow a potential adversary the shelter of neutrality, if it repre- sented an advantage for the state’s enemies. 25. Walt, The Origins of Alliances, pp. 29–30. 26. Thomas C. Schelling, The Strategy of Conºict (New York: Oxford University Press, 1963), p. 177; and David A. Baldwin, Paradoxes of Power (New York: Basil Blackwell, 1989), pp. 56, 69–71. The proposition that dividers are more likely to try a confrontational approach against adversaries they perceive as fractious may subsume a variety of narrower, case-speciªc explanations. See, for example, Robert Jervis, “Deterrence and Perception,” International Security, Vol. 7, No. 3 (Winter 1982/83), p. 23.

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ward power” to selectively accommodate any of its adversaries. Second, the state lacks strong allies to help it deal with the threat. Under these circumstances, the state is compelled to act but bereft of alternatives to coercion, and it has little to lose because relations with its adversaries are already poor.27 summary. Dividers will prefer selective accommodation strategies when they are likely to matter most, that is, when a dangerous alliance is likely to form or persist and the divider has some ability to use inducements to counter- act the threat. By contrast, states are more likely to opt for confrontation when dividing their adversaries seems easy or less important, or when they have no other choice. Either way, such strategies are unlikely to greatly beneªt the divider. In the ªrst scenario, the divider confronts its adversaries because they seem prone to disunity or their unity does not pose a great danger, or both. In the second set of circumstances (identiªed by Izumikawa), the divider tries confrontation even though it is almost certain to backªre: the divider is grasp- ing at straws, and the situation cannot become much worse. To better understand how and when selective accommodation strategies are likely to achieve success, I incorporate two factors into the analysis: (1) the target’s costs of alignment change and (2) the divider’s costs of inducing it.28

the importance of neutral alignment outcomes The goal of a wedge strategy—the alignment change being sought— conditions the prospects of success and the range of techniques dividers can use to promote it. To generate signiªcant movement, a selective accommodation strategy must offer the target rewards that exceed its costs of alignment change. Because big alignment changes generally cost targets more to make than little alignment changes, dividers incur greater costs to induce big changes.29 In countervailing situations, this is especially true. There are four major alignment aims and outcomes of interest. From most to least difªcult to induce, they are realignment, dealignment, prealignment, and disalignment.30

27. Izumikawa, “United We Stand, Divided They Fall,” p. 46. 28. See David A. Baldwin, “Success and Failure in Foreign Policy,” Annual Review of Political Sci- ence, Vol. 3 (June 2000), pp. 174–175. 29. This discussion does not imply that the outcomes of wedge strategies must reºect strategic intentions. Sometimes, a modest political separation will result from an attempt to achieve a much greater degree of division. 30. A ªfth “preclusive” aim seeks to remove an uncommitted power from a pool of potential adversaries by making it an ally. Although it has a divisive aspect, this aim is so close to the straight- forward logic of alliance making that I do not address it here. The paradigmatic example of a preclusive alliance is Germany’s 1879 pact with Austria-Hungary, which Otto von Bismarck sought “primarily to prevent Austria from allying with France and Russia or France and Eng-

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Strategies that pursue dealignment or prealignment (i.e., neutral alignment outcomes) are the most likely to generate signiªcant countervailing effects. realignment. Realignment strategies seek to shift a target from an opposing alliance to a friendly one. If the opposing alliance is at all cohesive, this goal is impossible to achieve through confrontation and hard to accomplish with inducements. The kind of defection that is most damaging to a target’s alliance reputation is a Brutus-like betrayal.31 To induce such a defection, the divider must offer rewards signiªcant enough both to compensate the target for the blow it will suffer to its credibility and prestige and to beneªt the target strategically. During World War I, Germany tried numerous times to convince Japan to switch sides, by offering to write off its conquests of German territories in Asia at war’s end and provide it with generous economic rewards. With Japan already in possession of these territories, however, it was weak tea.32 If the sought-after defection also means that the target moves from nonbelligerence to co-belligerence, its rewards must be even greater. Not only does the divider need to generate large and credible inducements to break the alliance, but it also must make new costly strategic commitments to the target. States rarely attempt realignment against cohesive allies, because it is nearly certain to fail: few countries would choose to become open enemies of close allies merely for the sake of rewards, and dividers will not pay the up-front costs necessary to convince a would-be target to take such a step. Realignment attempts do not succeed unless they can exploit a serious conºict between the target and its allies; thus, such successes tend to have weak countervailing effects. dealignment. A divider using a dealignment strategy tries to induce the target’s neutrality, a less costly and less dangerous form of defection than realignment. The target must still pay the reputational and strategic costs of abandoning an ally, but it can ªnesse its defection through rhetorical sophistry, legalistic treaty interpretation, and claims of unpreparedness, in a way that it could not if it ºagrantly switched sides. Dividers often try to promote dealign- ments and succeed with some frequency, even in countervailing situations, because they can offer inducements sufªcient to outweigh the target’s costs of

land.” Quoted in Snyder, Alliance Politics, p. 14; see also p. 44. In addition, see Frank Zagare, The Games of July: Explaining the Great War (Ann Arbor: University of Michigan Press, 2010), pp. 87–88. 31. On the concept of alliance reputation, see Gregory D. Miller, “Hypotheses on Reputation: Alli- ance Choices and the Shadow of the Past,” Security Studies, Vol. 12, No. 3 (Spring 2003), pp. 40–78; and Douglas M. Gibler, “The Costs of Reneging: Reputation and Alliance Formation,” Journal of Conºict Resolution, Vol. 52, No. 3 (June 2008), pp. 426–454. 32. Frank W. Iklé, “Japanese-German Peace Negotiations during World War I,” American Historical Review, Vol. 71, No. 1 (October 1965), pp. 62–76.

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becoming neutral. A dealignment strategy may also serve a preventive purpose: to neutralize a target before its commitment to an ally grows stronger. In such cases, the divider must pay the target’s costs of reneging on an existing commitment, plus the costs of forgoing the beneªts of a stronger commitment (which the target’s ally may seek to bid up). The political consequences of successful dealignment strategies can be signiªcant; alliances are broken that would have otherwise remained intact or become stronger. prealignment. A prealignment strategy seeks to preserve the neutrality of a target that is not yet formally allied, but is prone to join the enemy camp. Perceiving that propensity, the divider acts to forestall further movement in this direction. Other things being equal, inducing a target to remain neutral is easier—and less costly—than trying to detach it after it has joined an alliance. Formal alliances do raise barriers—in the form of costs—to reneging on commitments;33 those costs, however, do not have to be covered in the bargain the divider offers to preserve the target’s neutrality. Still, the divider must pay to prevent a target that is leaning toward allying with the other side from taking this next step, especially when tensions are rising and pressures to declare alle- giances are increasing. When dividers successfully induce the neutrality of states that would otherwise join a hostile alliance, the strategic gains can be signiªcant, even though the observable results are less marked. disalignment. A divider using a disalignment strategy seeks to weaken a target’s cooperation within an opposing bloc, without trying to convert the target into a neutral or an ally. Enticing targets into such bargains is relatively easy, because targets do not have to pay the costs of defection to beneªt from them. Ideally, the divider’s policy will create or aggravate tensions between the target and its allies and, beyond that, reward the target for adopting policies that weaken their collaboration. An initiative that simply elicits from the target a willingness to negotiate can produce the ªrst effect, even if the talks produce no substantial agreement.34 The divider’s inducement only needs to be attractive enough to make the target willing to risk friction with its allies in order to obtain (or explore the possibility of obtaining) it. Disalignment strategies are often attempted and successful, but they generally have limited countervailing effects.

33. On this point, see Snyder, Alliance Politics, pp. 44, 353–357; and James D. Morrow, “Alliances: Why Write Them Down?” Annual Review of Political Science, Vol. 3 (June 2000), p. 65. 34. As Fred Charles Iklé observed, the willingness to negotiate on equitable terms with one party but not others in an opposing group can “stir up fears” among those “left out” that “a deal might be made at their expense.” Iklé, How Nations Negotiate (New York: Praeger, 1964), p. 57.

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summary. This overview of a potential divider’s alignment objectives sheds light on how and when selective accommodation wedge strategies work.35 First, it explains why promoting neutral outcomes works best in countervailing conditions. Realignments, except when there are deep, exploitable cleav- ages, are not obtainable; and disalignments, though easier to achieve, have limited strategic signiªcance. Second, the overview underscores that the divider’s costs of accommodation are related to the outcomes it is pursuing. Below I discuss the different forms of selective accommodation and their costs to the divider, as well as how variation in these forms of selective accommodation inºuences both their use and effectiveness.

appeasement, compensation, and endorsement There are three main forms of selective accommodation: appeasement, compensation, and endorsement (see table 1). Each rewards the target on issues to which it attaches major importance. Appeasement is the most costly type of selective accommodation: the divider offers a direct concession to the target that is of primary interest to the divider. Compensation, which uses inducements based on secondary interests, is less costly.36 Endorsement is usually the least costly: here, the divider supports the target’s position in a conºict between the target and the target’s ally. All three forms of selective accommodation can in- volve speciªc or general linkage.37 In a speciªc linkage strategy, conditionality is strong and formal: the divider demands that the target makes an explicit alignment change in return for a concession. In a general linkage strategy, conditionality is weak and informal: the divider tries to elicit the desired alignment change indirectly. When the risk of war is high or conºict is spreading,

35. There are other important implications. First, timing can matter. An inducement sufªcient to maintain a target’s neutrality may not be able to neutralize the target if it decides to join an opposing alliance, because the costs of its alignment change have increased. Second, a divider lacking the means to induce a dramatic change may nevertheless be able to induce division at lower levels. Third, even if a divider has the resources to pursue larger alignment changes, its strategic calculus may favor lesser relational aims: for example, the divider may be better off neutralizing an adversary than converting it to an ally. 36. Thus, compensation in this context represents a reversal of the more intuitive use of economic incentives as a tool to bolster one’s alliances and position within them. See Christina L. Davis, “Linkage Diplomacy: Economic and Security Bargaining in the Anglo-Japanese Alliance, 1902– 23,” International Security, Vol. 33, No. 3 (Winter 2008/09), pp. 143–179. On concessions and compensation, see James W. Davis Jr., Threats and Promises: The Pursuit of International Inºuence (Balti- more, Md.: Johns Hopkins University Press, 2000), pp. 14–16. 37. On this distinction, see Randall E. Newnham, “More Flies with Honey: Positive Economic Linkage in German Ostpolitik from Bismarck to Kohl,” International Studies Quarterly, Vol. 44, No. 1 (March 2000), pp. 81–82; and Drezner, “The Trouble with Carrots,” p. 189.

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Table 1. Selective Accommodation Wedge Strategies: Relative Frequency and Effectiveness

Forms Specific Linkage General Linkage

Appeasement Attempts are rare. Usually last- Attempts are rare. Can work as (primary minute crisis maneuvers that come long-run bids to promote interest) too late and fail. conciliation and realignment. Compensation Attempts are more common. More Attempts are more common. More (secondary likely to succeed in promoting likely to succeed in promoting interest) neutral outcomes and disalignment. neutral outcomes and disalignment. Endorsement Attempts are rare. Key element of Attempts are common. Useful for (tertiary successful realignments. promoting disalignment and interest) supporting compensation.

the divider’s urgency and inducement costs climb, and speciªc linkage be- comes the rule. General linkage is more common and more useful when there is a longer time horizon and the political costs of extending concessions are lower. I make three key arguments about the use and effectiveness of the three main forms of selective accommodation. First, appeasement is rarely used because it is the most costly. Dividers will not try speciªc linkage, in particular, unless they are desperate. Even then, it rarely works. Second, speciªc and general linkage compensation is more common and more likely to work. On the one hand, dividers have greater leeway and greater willingness to trade secondary interests for alignment changes in a credible and timely fashion; on the other hand, the rewards can be sufªciently attractive to induce neutral alignment outcomes. Third, endorsement as a general linkage maneuver is also a common and easy way to reinforce neutrality or disalignment. More rarely, endorsement works in speciªc linkage bids for realignment, by capital- izing on a signiªcant cleavage between a target and its allies. appeasement. A divider using an appeasement wedge strategy seeks to detach its target by offering a primary—usually territorial—asset (e.g., contig- uous territory, a strategic waterway, or an overseas possession) that is under the divider’s exclusive control and on which the target has made claims.38

38. By “primary,” I do not mean that the interests or assets are “vital” in the sense that the nation could not survive without them. Rather, they are highly valued and under the exclusive (“private”) control of the state. An example of speciªc linkage appeasement is Israel’s withdrawal from territory in the Sinai in exchange for a separate peace treaty with Egypt, which dealigned Egypt from the Arab rejectionist bloc. On the distinction between “private” and “shared” rewards, see

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Appeasement should be a highly effective way to produce big alignment change.39 The conditions for success are not easily met, however, especially in an atmosphere of crisis. Once adversaries are circling with demands, appeasement can work only if the divider remains strong after the exchange is made, and if it is able to credibly signal the limits of its ºexibility.40 The divider needs to convey that its willingness to concede is unique to the divider’s rela- tionship to the target and to the prevailing context. The target must be con- vinced that it will not receive similar acquiescence on matters of even greater importance to the divider. In addition, other adversaries must be deterred from believing that their demands will produce similar concessions. Other- wise, a vicious cycle will begin.41 The high costs and risks of appeasement wedge strategies deter most dividers from using them. Dividers willing to re- sort to appeasement usually face, or intend to hazard, imminent war against a dangerous alliance, and they demand quick alignment changes. These speciªc linkage attempts made under duress usually fail because they come too little, too late, and lack credibility. An example is Austria-Hungary’s eleventh-hour attempts to appease Italy by conceding the Trentino in April–May 1915, as it became clear that Italy was about to join the Entente in pursuit of larger gains.42 Wedge strategies based on general linkage appeasement are also rare. States that are survival minded generally do not offer primary assets to potential ad-

Davis, Threats and Promises, pp. 20–21. On the general concept of appeasement, see Ripsman and Levy, “Wishful Thinking or Buying Time?”; Andrew Barros, Talbot C. Imlay, and Evan Resnick, “Correspondence: Debating British Decisionmaking toward Nazi Germany in the 1930s,” Interna- tional Security, Vol. 34, No. 1 (Summer 2009), pp. 173–198; and Stephen R. Rock, Appeasement in In- ternational Politics (Lexington: University Press of Kentucky, 2000). 39. First, because appeasement offers the target high-value rewards, it will be more likely to tip the target’s cost-beneªt calculus in favor of alignment change. Second, because it entails high-cost concessions, appeasement will be more likely to dispel perceptions of the divider as a threat that the target shares with other adversaries. Third, a prudently timed territorial transfer can reshufºe the target’s strategic interests, putting the target into a position less compatible with the objectives of its erstwhile allies. 40. Secrecy is also likely to be an important component of the attempt, because the divider will not want its potential willingness to concede a primary interest to be more widely perceived as general weakness (and also because the target may not wish to rupture existing relationships prema- turely). These wider reputational concerns prevent the frequent use of bad-faith appeasement bids as a disalignment stratagem. 41. See Quincy Wright, A Study of War, abridged (Chicago: University of Chicago Press, 1964), pp. 132–133. 42. For details of this episode, see Leo Valiani, “Italian-Austro-Hungarian Negotiations, 1914– 1915,” Journal of Contemporary History, Vol. 1, No. 3 (July 1966), pp. 113–136. France’s attempts in late May 1940 to perpetuate Italy’s nonbelligerence through appeasement were similarly doomed. William I. Shorrock, From Ally to Enemy: The Enigma of Fascist Italy in French Diplomacy, 1920–1940 (Kent, Ohio: Kent State University Press, 1988), pp. 283–284.

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versaries in goodwill gestures that leave the alignment payoff unspeciªed and to be collected later. This is especially true when the target is already en- sconced in the opposing camp. When tensions are running lower, or the target is not a committed adversary, however, dividers may use conciliation more prudently to ensure the neutrality of a target or even to begin nudging it toward partnership.43 For such reasons, states do sometimes agree to “rectify” borders, transfer territory, begin joint control over strategic routes, and so on. Taking the initiative before crises erupt lowers the divider’s reputational costs. In 1962, for example, China moved to resolve its border disagreement with Pakistan on decidedly generous territorial terms. Having just imposed a hu- miliating defeat on India over another border dispute, and having established its resolve on territorial matters, China was in a position that did not require it to oblige Pakistan, and yet it chose to do so. This was not appeasement under the gun. But in conciliating Pakistan, Beijing spoiled a U.S. initiative to broker an agreement between Pakistan and India meant to usher in a U.S.-backed South Asia anticommunist alliance.44 compensation. A compensation wedge strategy offers the target inducements drawn from the divider’s secondary interests. Speciªc and general linkage compensation strategies are common, and both are useful in promoting neutral alignment and disalignment gains. The divider’s inducements may in- volve adjustments to its peripheral territorial claims or spheres of inºuence, ties to partners and allies, economic relations and privileges, policies and positions of inºuence in international organizations, or a willingness to negotiate other issue-speciªc agreements or regimes. To promote alignment change, the divider tries to capitalize on critical levers, issues, and values that matter more to the target than to the divider, but that are largely under the divider’s control. Historically, during periods of crisis, dividers often linked peripheral territorial compensation to the neutrality of potential adversaries. France’s victory against Austria and Russia at the 1805 Battle of Austerlitz, for example, was fa- cilitated by Prussian neutrality, which Napoleon procured by “giving Hanover to Prussia.”45 Such traded territories can be carved out of prospective—as well

43. Rock, Appeasement in International Politics, p. 13. 44. In granting Pakistan’s territorial claims, China also endorsed Pakistani claims against India. See Timothy W. Crawford, Pivotal Deterrence: Third-Party Statecraft and the Pursuit of Peace (Ithaca, N.Y.: Cornell University Press, 2003), p. 146; and M. Taylor Fravel, Strong Borders, Secure Nation: Cooperation and Conºict in China’s Territorial Disputes (Princeton, N.J.: University Press, 2008), pp. 116–117. 45. D.G. Wright, Napoleon and Europe (London: Longman, 1984), p. 47; and R.B. Mowat, The Diplo-

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as past—victims of expansion, which makes it even easier to parlay them, if the target is interested in their fate.46 Compensation may also take the form of cooperation or exchange mechanisms that produce “shared” rewards (e.g., through trade and ªnancial relationships or arms control agreements). Such mechanisms can be speciªcally linked to neutral alignment goals, as was Britain’s provision of economic aid to Francisco Franco’s Spain in 1941 to prevent it from joining the ranks of Germany and Italy as a belligerent. To gain and sustain access to the British aid it badly needed, Spain had to meet two concrete conditions: remain a nonbelligerent, even though its Axis partners were at war with Britain, and publicly acknowledge receiving the aid, an act that would distance Madrid from Berlin and Rome and produce supporting domestic political effects.47 Territorial and economic compensation can also be bundled in speciªc linkage deals. In World War II, Germany tried to realign Turkey by extending favorable trade relations to the Turks and offering to support Turkish expansion in Iraq, Syria, and the Dodecanese. Although the German effort did not cause Turkey to realign, it did contribute to Ankara’s decision to renege on Turkey’s alliance with Britain and remain neutral.48 A more signiªcant and observable success of inducements appeared with the 1939 Nazi-Soviet nonaggression pact, where Hitler offered to open channels of trade beneªcial to Moscow and invited Soviet expansion into Poland, the Baltics, and the Balkans.49 With general linkage compensation, results are less immediate and often less obvious. There may still be a two-way agreement that requires the target to cooperate on a speciªc issue (e.g., a new trade treaty), but the larger alignment objective comes as a second-order result. Thus, when Napoleon sold the Louisiana territory to the United States to divert it from joining an alliance with Britain, the speciªc quid pro quo was a land-for-cash exchange; continuing U.S. neutrality was an indirect consequence.50 Economic exchange ar-

macy of Napoleon (New York: Russell and Russell, 1971), p. 147. The Hanover transfer had the added advantage of straining relations between Britain and Prussia. 46. On this point, see Schweller, Deadly Imbalances, pp. 77–78. 47. Crawford, “Wedge Strategy, Balancing, and the Deviant Case of Spain, 1940–41.” 48. Frank G. Weber, The Evasive Neutral: Germany, Britain, and the Quest for a Turkish Alliance in the Second World War (Columbia: University of Missouri Press, 1979), chaps. 2–3. 49. On these economic inducements, see Randall Newnham, Deutsche Mark Diplomacy: Positive Economic Sanctions in German-Russian Relations (University Park: Pennsylvania State University Press, 2002), pp. 98–101. On territorial compensations, see Geoffrey Roberts, Stalin’s Wars: From World War to Cold War, 1939–1953 (New Haven, Conn.: Yale University Press, 2006), pp. 33–34. 50. See Colin Elman, “Extending Offensive Realism: The Louisiana Purchase and America’s Rise to Regional Hegemony,” American Political Science Review, Vol. 98, No. 4 (November 2004), pp. 567, 572, 574.

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rangements that generate disproportionate beneªts for the target—while increasing the target’s vulnerability should the divider threaten to withdraw from them—are particularly useful in such compensation strategies. They are natural tools for dividers seeking neutral alignment gains over the long term. As with appeasement, states that seek the realignment or dealignment of a target through general-linkage economic aid risk “feeding the enemy” for naught. Both strategies can still be useful, however, when the divider is strong, the situation is not urgent, and disalignment is an acceptable outcome. Thus, when a split between Yugoslav leader Josep Broz Tito and Soviet leader Joseph Stalin emerged in 1948, Harry Truman’s administration followed George Kennan’s advice to expand direct economic support to Yugoslavia with few conditions. Doing so would allow Yugoslavia to “continue to exist as an ero- sive and disintegrating force operating within the Kremlin’s power sphere.”51 In addition, arrangements that emphasize shared rewards help to minimize the costs of feeding an enemy for naught. France, for example, employed this approach to undermine Italy’s commitment to the Triple Alliance, when it adopted a most-favored-nation trade agreement with Rome in 1898. This decision marked the end of an infamous ten-year Franco-Italian tariff war that, perversely, had done much to deepen Italy’s strategic ties to Germany.52 The French “policy of winning Italy away from the Triple Alliance by kind- ness” was, as one historian put it, “eminently successful.”53 That success laid the groundwork for a more concrete, albeit secret, dealignment in 1902, which would ultimately help neutralize Italy at the outbreak of World War I. Before that major payoff, however, the policy also beneªted French trade— a factor that sustained the policy during the sixteen years that Italy remained formally committed to the enemy camp. endorsement. Employing an endorsement wedge strategy, the divider ma- nipulates its position on a tertiary interest—speciªcally, a dispute between its adversaries. The divider inserts itself into that dispute by backing one side, with greater or lesser levels of commitment, on an issue that typically matters much more to the disputants than to the divider. Endorsements can be the least costly form of selective accommodation. They often manifest as cheap talk—rhetorical or symbolic diplomatic pronouncements in bilateral summits

51. Gregory Mitrovich, Undermining the Kremlin: America’s Strategy to Subvert the Soviet Bloc, 1947– 1956 (Ithaca, N.Y.: Cornell University Press, 2000), p. 38. 52. William A. Renzi, In the Shadow of the Sword: Italy’s Neutrality and Entrance into the Great War, 1914–1915 (New York: Peter Lang, 1987), pp. 9–10. 53. Walter B. Harvey, Tariffs and International Relations in Europe, 1860–1914 (Chicago: University of Chicago Press, 1938), p. 213.

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or international forums. Less often, dividers back their endorsements with more resources and stronger commitments, which increase not only their costs but also their inºuence. When they work well, endorsements encourage the target to press its grievances and make its allies—sensing betrayal—less ºex- ible, thus elevating the importance of the conºict in the disputants’ overall re- lationship. But unless the conºict already has major signiªcance, and the endorsement is matched with strategic commitments, this form of selective accommodation is unlikely to produce dramatic ruptures within an opposing alliance. The costliest endorsements are thus speciªcally linked to realignment. The divider buys the target’s allegiance by underwriting the target’s claims against its erstwhile ally. A notable success was Britain’s 1915 offer to back Italian territorial claims against Austria-Hungary, if Italy entered the war against the Central Powers. To win Rome over, London promised not only to endorse Italy’s conquest of Trentino, but to sustain the war until the Italians gained Trieste and achieved additional aims on the Adriatic.54 An illuminating failure was Germany’s infamous Zimmermann telegram of 1917, which offered to back Mexican claims to parts of the southwestern United States if Mexico went to war against its northern neighbor.55 An obvious weakness of the offer was Germany’s doubtful ability to provide major material support to Mexico. Di- viders generally will not embrace commitments to bolster targets’ ambitions without extracting speciªc cooperation against adversaries. Thus, costly general linkage endorsements are rare. General linkage endorsements are, commonly, low-cost maneuvers. In the late 1970s, for example, the Soviet Union reinforced Vietnam’s deepening alienation from China by taking Hanoi’s side over their competing claims to the Spratly Islands.56 For Moscow, the decision to shift from disinterest to support for Vietnam’s claim was easy: it had neither a claim nor aspirations to the islands. Soviet support for Vietnam’s position was not explicitly tied to the re- quirement that Hanoi become more actively hostile to China—Moscow was betting that this would be the natural effect in an already worsening conºict. General linkage endorsements can be a cheap, cost-effective way to promote disalignment. In the mid-1960s, for example, the Soviet Union stoked the

54. David French, British Strategy and War Aims, 1914–1916 (Boston: Allen and Unwin, 1986), p. 86. 55. Although the United States and the Carranza regime in Mexico were not allies in 1917, they did have friendly relations. See Barbara W. Tuchman, The Zimmermann Telegram (New York: Ballentine, 1994). 56. Robert S. Ross, Indochina Tangle: China’s Vietnam Policy, 1975–1979 (New York: Columbia Uni- versity Press, 1988), especially p. 130.

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Cyprus dispute between NATO allies Greece and Turkey, ªrst by rhetorically supporting the Greek position when Athens was most inclined to force matters, and then by switching to rhetorical support for the Turkish position when Ankara was most aggressive.57 Moscow’s switch to the Turkish side accompa- nied a larger rapprochement with Ankara, but it was not linked to a demand that Turkey withdraw from NATO. The Soviets would encourage ªssures in NATO’s southern ºank indirectly, rather than trying to extract them overtly. Nonterritorial disagreements among allies also invite attempts to disalign through coordination. In the early 1960s, for example, the John F. Kennedy administration made concessions to win Soviet agreement to the Limited Test Ban Treaty (LTBT), hoping to exploit a rift between Moscow and Beijing over the development of a Chinese nuclear weapon.58 As tools of inºuence, endorsements have important limitations. First, a state’s adversaries may not be engaged in salient disputes that a divider can exploit; thus the least costly approach will not be an option in the hardest cases.59 In addition, when such disputes are salient and successfully exploited, the impact of the endorsement is easy to overstate.60 Second, endorsement wedge strategies are the most vulnerable to countermeasures. The issue the divider seeks to exploit is, ultimately, more subject to the adversaries’ control; the divider does not have unique or prevailing inºuence over its disposition. A country whose alliance is likely to be strained by a divider’s endorsement may—if the target is important enough—resolve the disagreement in the target’s favor. Thus, in 1938 Hitler blunted Britain’s efforts to derail an Italo- German pact by agreeing to repatriate Germans from the Alto Adige, an Italian region that looked vulnerable to a Sudeten-like coup and that Mussolini was anxious to defend. summary. Wedge strategies that have the greatest impact in power politics selectively compensate targets to promote neutral alignment outcomes. This is a relative claim; it does not mean that such wedge strategies will succeed with high frequency in countervailing situations. It does mean that dividers will

57. See Crawford, Pivotal Deterrence, pp. 118–121. 58. See Glenn T. Seaborg, Kennedy, Khrushchev, and the Test Ban (Berkeley: University of California Press, 1981); and Gordon Chang, Friends and Enemies: The United States, China, and the Soviet Union, 1948–1972 (Palo Alto, Calif.: Stanford University Press, 1990), p. 249. 59. What Patricia Weitsman identiªes as “tethering alliances”—alliances designed to manage conºict between two parties and contain the threats they pose to each other—are thus easy targets for endorsement wedge strategies. See Weitsman, “Intimate Enemies: The Politics of Peacetime Al- liances,” Security Studies, Vol. 7, No. 1 (Autumn 1997), pp. 156–193. 60. Thus, Lorenz Lüthi argues that the LTBT had a small effect on the breakdown of Sino-Soviet relations, because “in the end, Mao’s renewed radicalism had prepared the ground for the Sino- Soviet rift; the [LTBT] treaty simply helped it to burst into the open.” Lüthi, The Sino-Soviet Split, pp. 271–272.

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often try them because the opportunities and prospects for success are suf- ªciently plausible, and their efforts will sometimes succeed with important consequences for international politics.

Implications of Wedge Strategies for International Power Politics

The ability of defensive dividers to use selective accommodation strategies to neutralize members of aggressor coalitions has important implications for theories of balancing and for how scholars assess external balancing efforts in speciªc cases, as well as for their prevalence in international politics more broadly. That offensive dividers can use similar strategies to prevent or dis- solve blocking coalitions has signiªcant implications for theories of balancing failure, for how scholars should analyze failure in speciªc cases, and for the larger question of the importance of balancing in international politics, given the frequency of balancing failures. I discuss these implications in more detail below, as well as their import for understanding historical cases and contemporary international security issues.

defensive wedge strategies and external balancing Defensive divide-and-balance wedge strategies aim to prevent or disband threatening alliances. If, as Norman Angell put it, power politics are “the politics of not being overpowered,” these strategies are central to that enterprise.61 In realist theory, states try to avoid being overpowered by engaging in balancing; they build strength through internal means and external relations to counter threats. There is, however, an additive bias in the way most scholars think about external balancing (i.e., as states’ attempts to “aggregate” power against threats) that obscures the central role that defensive wedge strategies can play in balancing behavior, in particular, by promoting neutral alignment outcomes.62 Using a defensive wedge strategy, balancers can break up and disorganize potential aggressors, and weaken and isolate the main threats. The concept of a defensive wedge strategy implies that efforts to neutralize or disalign opponents through selective accommodation can partially substitute for more observable arms and alliance building in states’ portfolios of balancing tools.63 To overlook the issue of substitutability is to invite misjudg-

61. For Angell, the godfather of early twentieth-century liberal internationalism, the statement reºected a late appreciation of realist prudence. Angell, quoted in Michael Howard, War and the Liberal Conscience (New York: Columbia University Press, 2008), at p. 116; see also p. 94. 62. The bias is entrenched in equating external balancing with the making of alliances. 63. The literature on foreign policy substitutability also suffers from the additive bias noted above, which usually reduces the menu of responses to threat to a choice between more arms or more al-

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ments about the prevalence of balancing in international politics and the timing and impact of balancing efforts in critical historical contexts.64 When the level of arming or alliance building that scholars expect to see in response to a growing threat is not evident, it could be because a defensive wedge strategy, angling for less observable power gains, may be at work. Indeed, when states face a growing composite threat, and the options to rearm and recruit allies are constrained by high costs or otherwise precluded, states should make extra efforts to neutralize and disalign adversaries. If such efforts are weak or absent, then there is a failure to balance externally that needs to be explained. If such efforts are made, then the balancing response is engaged, and if these efforts impede or disorganize threatening blocs, then balancing worked, even if the effect is only to delay aggression or curtail its scope.65 This conception of balancing suggests that Britain did more to balance externally against Germany in the late 1930s than is often thought.66 Britain’s responses to the German threat after the reoccupation of the Rhineland in March 1936 look less tardy and anemic when one views certain British actions as attempts to use a defensive wedge strategy to keep Italy and Germany apart. These attempts began in mid-1936 and continued consistently through 1939 (even after war broke out) against the backdrop of relations poisoned by Italy’s aggression in Ethiopia and Britain’s leadership of a League of Nations sanctions effort against Italy. In this policy, which stressed accommodation through a series of compensations, British leaders did not try to turn Italy into an active opponent of Germany (as they had in earlier years), but to weaken and eventu- ally neutralize Italy’s position in the Axis triple threat then coalescing. In May 1936, two months after Hitler’s move into the Rhineland, the British government began seeking avenues for accommodation with Italy: in particu-

lies. See, for example, Benjamin Most and Harvey Starr, “Substituting Arms and Alliances, 1870– 1914: An Exploration in Comparative Foreign Policy,” in Charles F. Hermann, Charles W. Kegley Jr., and James N. Rosenau, eds., New Directions in the Study of Foreign Policy (Boston: Unwin and Hyman, 1987), p. 134; Benjamin A. Most and Harvey Starr, “International Relations Theory, For- eign Policy Substitutability, and ‘Nice’ Laws,” World Politics, Vol. 36, No. 3 (April 1984), p. 387; and James D. Morrow, “Arms versus Allies: Trade-Offs in the Search for Security,” International Organi- zation, Vol. 47, No. 2 (Spring 1993), p. 208. See, however, Glenn Palmer and T. Clifton Morgan, A Theory of Foreign Policy (Princeton, N.J.: Princeton University Press, 2006), chap. 7. 64. On this point, see Jack S. Levy, “Balances and Balancing: Concepts, Propositions, and Research Designs,” in Vasquez and Elman, Realism and the Balancing of Power, p. 138. 65. On the need to think about timing and degree in balancing assessments, see ibid., pp. 134–135. 66. On this point, see also Barry R. Posen, The Sources of Military Doctrine: France, Britain, and Ger- many between the World Wars (Ithaca, N.Y.: Cornell University Press, 1984), p. 170; and Schweller, Deadly Imbalances, p. 75. For a view of Britain as a sluggish external balancer, see Robert G. Kaufman, “To Balance or to Bandwagon?’ Alignment Decisions in 1930s Europe,” Security Studies, Vol. 1, No. 3 (Spring 1992), pp. 417–447.

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lar, it sought to leverage Britain’s inºuence over the sanctions issue.67 At the League of Nations assembly in July 1936, British Foreign Secretary Anthony Eden called for lifting the sanctions on Italy, a call that was heeded almost im- mediately. Later that month, Britain retracted security assurances to Greece, Turkey, and Yugoslavia, which it had extended to encourage their support in sanctioning Italy. As Foreign Secretary Eden explained to the French, the compensations to Italy would serve Anglo-Franco interests “because the probabil- ity of a ªrm German-Italian bloc would thereby be lessened.”68 Later in the year, as the Spanish Civil War unfolded and Italy intervened openly, the British stepped up their efforts to secure a more tangible accommodation with Rome. Britain’s renewed efforts were precipitated not by frictions between Italy and Germany, but by increasing indications of the two countries’ conver- gence: in particular, the Italian foreign minister’s mission to Berlin in October 1936. A determined British effort to undercut that dynamic produced the January 1937 Anglo-Italian “Gentleman’s Agreement,” concerning Britain’s and Italy’s interests in Mediterranean affairs. When the agreement was struck, Undersecretary of the Foreign Ofªce Robert Vansittart minuted, “[I]f we never talk of detaching them [i.e., Italy] from Germany, but merely exploit this success...weshall automatically loosen the Italo-German tie.”69 The desire to prevent Germany and Italy from growing closer was also behind the diplomatic drive that culminated in the Anglo-Italo “Easter accords” of April 1938, wherein Britain agreed to seek League of Nations recognition of Italian conquests in Ethiopia in return for a variety of steps to reduce Anglo- Italo tensions.70 Since May 1937, British leaders had been looking for a way to use ofªcial recognition of Italy’s empire in Ethiopia to improve relations with Rome and thus distance the Italians from the Germans. The initiative gained steam in early 1938, after Italy joined Germany and Japan in the Anti-Comintern pact—a political alliance that was formally against International Communism and the Soviet Union, but also informally

67. Christopher Seton-Watson, “The Anglo-Italian Gentleman’s Agreement of January 1937 and Its Aftermath,” in Wolfgang J. Mommsen and Lothar Kettenacker, eds., The Fascist Challenge and the Policy of Appeasement (London: Allen and Unwin, 1983), p. 268. 68. DBFP, 2d ser., Vol. 17, p. 462. Similarly, in December 1936 Vansittart argued that British policy should try to “detach Italy from any extreme complicity with Germany,” and “by moreover detaching her from Germany render her more improbable everywhere.” Quoted in Aaron L. Goldman, “Sir Robert Vansittart’s Search for Italian Cooperation against Hitler, 1933–36,” Journal of Contemporary History, Vol. 9, No. 3 (July 1974), pp. 129–130. 69. Seton-Watson, “The Anglo-Italian Gentleman’s Agreement of January 1937 and Its After- math,” p. 275 (emphasis in original). 70. Reynolds M. Salerno, Vital Crossroads: Mediterranean Origins of the Second World War, 1935–1940 (Ithaca, N.Y.: Cornell University Press, 2003), pp. 49–51, 59–62.

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against the Western democracies—and withdrew from the League. Britain’s prime minister, Neville Chamberlain, hoped that by recognizing Italy’s Ethio- pian empire, the League would prompt Italy’s return—and thus help to isolate Germany. Chamberlain escalated the approach in early March, just before the Anschluss. German intervention in Austria made Mussolini more receptive, and the Easter accords soon followed. Indeed, Chamberlain’s efforts produced a modest success. In May 1938, Mussolini rebuffed Hitler’s aggressive bid to enlist Italy in a full-ºedged military alliance; the Italian dictator’s desire to preserve the prospects of gaining compensations from Britain and France drove that refusal.71 Italy would not commit to a formal military alliance with Germany until it signed the so-called Pact of Steel on May 22, 1939. Even after the announcement of the pact, Britain continued to pursue dealignment and disalignment through initiatives to accommodate Italy. These efforts helped to promote Italy’s “nonbelligerent” position when war broke out in September 1939.72 Italy’s defection to this form of neutrality would last until Germany crushed Western defenses in May–June 1940. From mid-1936 until mid-1940, then, Britain engaged in a sustained, sometimes successful, external balancing effort by distancing Italy from Germany. That defensive wedge strategies are a substitutable form of balancing helps to illuminate the contemporary phenomenon of “soft balancing” against U.S. primacy. Soft balancing is deªned as “actions that do not directly challenge [the] military preponderance [of a threat] but that use nonmilitary tools to delay, frustrate, and undermine [the threat’s] aggressive...military policies.”73 Perhaps the most important nonmilitary way to weaken and deter a threatening power is to divide its alliances.74 Scholars, however, who reject the thesis

71. See Donald Cameron Watt, “Britain, France, and the Italian Problem,” in Les Relations Franco- Britanniques: DE 1935 A 1939 [French-British relations: 1935 to 1939] (Paris: Centre Nationale de la Recherche Scientiªque, 1975), pp. 282–283; and Mario Toscano, The Origins of the Pact of Steel (Balti- more, Md.: Johns Hopkins University Press, 1967), p. 13. 72. Watt, “Britain, France, and the Italian Problem,” pp. 293–294; and Dennis Mack Smith, “Ap- peasement as a Factor in Mussolini’s Foreign Policy,” in Mommsen and Kettenacker, The Fascist Challenge and the Policy of Appeasement, p. 265. Italy’s lack of readiness for war and Berlin’s duplic- ity and failure to consult Rome in the lead-up to war in September 1939 were others reasons for It- aly’s defection. 73. Robert A. Pape, “Soft Balancing against the United States,” International Security, Vol. 30, No. 1 (Summer 2005), p. 10. 74. Pape alludes to the role of wedge strategies when he argues that as soft balancing against the United States intensiªes, it will “reduce the number of countries likely to cooperate with future U.S. military adventures.” Ibid., p. 10. But his accounting of soft-balancing mechanisms, which “include territorial denial, entangling diplomacy, economic strengthening, and signaling of resolve to participate in a [hard] balancing coalition,” omits wedge strategies. Ibid., p. 36. Similarly,

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that countries are engaging in soft balancing against the United States deªne balancing in a way that precludes the possibility of defensive divide-and- balance strategies.75 The omission virtually ensures the underestimation of the extent to which others are trying to reduce U.S. relative power. If, however, dividing alliances is a means of external balancing, then attempts to peel off and neutralize U.S. allies should count as soft balancing, not a routine form of diplomatic friction. Moreover, the proposition that such strategies can substitute for adding arms and allies provides a strong prediction related to soft-balancing logic: competitors constrained in their ability to gain strength against a threat with arms or allies should attempt to balance by dividing an opposing alliance. Given the United States’ military dominance and sprawling alliance systems, dealignment wedge strategies should therefore be the most useful nonmilitary way for states to reduce the relative strength of U.S. power. This result is less dangerous and much easier to achieve than a military counteralliance and more plausible than trying to catch up through internal arming. An important case in this regard is recent Russian diplomacy in Europe and Central Asia. Moscow is clearly in a defensive position vis-à-vis the expansion of U.S. power and U.S. allies in Russia’s near abroad. It is employing a strategy of selective bargains, using its energy exports to create disalignments among NATO members and to dissuade others from moving closer to the alliance.76 It has also attempted to leverage explicit economic and military inducements to persuade Central Asian states to close down U.S. military bases and attenuate their security ties to Washington.77 The strength of the substitution logic cuts both ways: if Russia was not attempting to dealign U.S.

T.V. Paul argues that soft balancing “involves the formation of limited diplomatic coalitions or en- tentes . . . with the implicit threat of upgrading their alliances if the United States goes beyond its stated goals.” T.V. Paul, “Soft Balancing in the Age of U.S. Primacy,” International Security, Vol. 30, No. 1 (Summer 2005), at p. 47; see also p. 58. 75. Stephen G. Brooks and William C. Wohlforth deªne external balancing as states “aggregating their capabilities with other states.” Brooks and Wohlforth, “Hard Times for Soft Balancing,” Inter- national Security, Vol. 30, No. 1 (Summer 2005), pp. 76–77. Likewise, Keir A. Lieber and Gerard Al- exander claim that soft balancing against the United States has not occurred because states have not “sought to pool their efforts or resources for counterbalancing.” Lieber and Alexander, “Waiting for Balancing: Why the World Is Not Pushing Back,” International Security, Vol. 30, No. 1 (Summer 2005), p. 109. 76. See Daniel Freifeld, “The Great Pipeline Opera,” Foreign Policy, No. 174 (September/October 2009), pp. 120–127; and Robert Marquand, “Russia Tries to Exploit Divisions in Europe,” Christian Science Monitor, September 3, 2008. 77. For in-depth analyses of Russia’s recent efforts, and hindrances to them, see Alexander Cooley, “Behind the Central Asian Curtain: The Limits of Russia’s Resurgence,” Current History, October 2009, pp. 323–332; and Bobo Lo, Axis of Convenience: Moscow, Beijing, and the New Geopolitics (Wash- ington, D.C.: Brookings Institution Press, 2008), chap. 6.

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military allies in its near abroad, then it would raise doubts about the soft- balancing thesis. That Russia is continuing these efforts helps to conªrm it.

offensive wedge strategies and balancing failure Both offensive and defensive realists expect that anticipated counterbalancing will check expansionist behavior.78 I argue, however, that an expansionist that expects counterbalancing may choose a wedge strategy instead of stasis. Ex- pansionists can therefore use offensive wedge strategies to prevent or disperse counterbalancing coalitions.79 Successful offensive wedge strategies produce external balancing failures. That much is obvious. Presuppositions about the prevalence and main drivers of external balancing failure, however, condition judgments about the strength and importance of such strategies. The neorealist literature argues that the pathology of buck-passing among would-be members of counterbalancing coalitions explains failures of external balancing. It casts buck-passing as a natural, “automatic” antibalancing dynamic among states facing a common threat, each looking to shift the costs of checking the threat onto others.80 This concept of buck-passing derives directly from Mancur Olson’s prisoner’s dilemma formulation of the collective action problem.81 That approach, as Glenn Stephens has shown, overlooks how outsiders “set up” the collective action problem to create and exploit cooperation failures. By eliding the role of the “district attorney” in creating the prisoner’s dilemma, the Olsonian paradigm “mismodels triadic interaction with [a] dyadic model.”82 In the same way, the buck-passing explanation identiªes the prime cause of balancing failure as cost-shifting competition among would-be balancers, but it omits the inºuence of wedge drivers in shaping this failure.83

78. See Jack S. Levy, “What Do Great Powers Balance Against and When?” in Paul, Wirtz, and Fortmann, Balance of Power, pp. 36–37; and Mearsheimer, The Tragedy of Great Power Politics, p. 37. 79. For recent works on this theme, see Goddard, “When Right Makes Might”; and Hui, War and State Formation in Ancient China and Early Modern Europe. 80. Richard Rosecrance, “Is There a Balance of Power?” in Vasquez and Elman, Realism and the Bal- ancing of Power, p. 159; Waltz, Theory of International Politics, pp. 164–170, 196–198; Posen, The Sources of Military Doctrine, pp. 63–64; Mearsheimer, The Tragedy of Great Power Politics, chap. 8; and Schweller, Deadly Imbalances, pp. 73–74. 81. In his seminal discussion of the buck-passing problem, Waltz cites Mancur Olson, The Logic of Collective Action: Public Goods and the Theory of Groups (Cambridge, Mass.: Harvard University Press, 1971), at pages 36 and 45, and states that “whether or not [buck-passing occurs] depends on the size of the group and the inequalities within it, as well as on the character of the members.” Note, here, that Waltz does not include the strategy of outsiders. Waltz, Theory of International Poli- tics, pp. 164–170, 196–198, quote at p. 165. 82. Glenn Hiram Stephens, “Sell Out, No Sell Out: The Politics of Artiªcial Social Traps,” Ph.D. dissertation, University of California, Los Angeles, 1992, pp. 12–13. See also Posner, Spier, and Vermeule, “Divide and Conquer,” pp. 11–13. 83. Thus, Mearsheimer’s account of the failure of Britain, France, and the Soviet Union to form a

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The neorealist explanation for balancing failures ªrst posits the presence of a threatening power that sets the expectation for a counterbalancing alliance, and then points to the dyadic “system” of potential balancers to explain why the expected alliance failed to form. This logic omits a crucial variable: the strategic behavior of the threatening power. States that provoke counterbalancing can also take steps to frustrate it; their offensive wedge strategies are a primary prior cause of the buck-passing dynamic. In at least some crucial cases, take away the wedge strategy, and the problem will subside or disappear.84 Some of the most important recent work on balancing failures begins to incorporate this insight: while stressing the role of collective action problems, it also points to a subordinate role for wedge strategies.85 Victoria Tin-bor Hui, for example, argues that actors seeking domination can exacerbate adversaries’ “already daunting” collective action problems through their own clever strategies.86 Thus, in Hui’s account of the wave of Chinese imperial expansion, the Qin dynasts were able to subordinate many surrounding potential blockers by playing on their proclivity to compete with one another through the offer of

balancing alliance against Germany in 1939 describes their efforts to shift the costs of confronting Germany onto others, but it says little about Hitler’s efforts to reach accommodation with Moscow in the summer of 1939, when the three powers were deeply engaged in alliance negotiations. Mearsheimer, The Tragedy of Great Power Politics, pp. 305–315. See also Stephen M. Walt, “Alliances, Threats, and U.S. Grand Strategy: A Reply to Kaufman and Labs,” Security Studies, Vol. 1, No. 3 (Spring 1992), p. 458. 84. An important kind of neoclassical realist explanation of balancing failure—most forcefully ex- pressed in Randall L. Schweller, Unanswered Threats: Political Constraints on the Balance of Power (Princeton, N.J.: University Press, 2006)—may be vulnerable to this line of criticism. That approach emphasizes domestic political discord over the need to balance, or whom to balance against, which causes imperiled states not to build effective alliances. Ibid., pp. 11–13. This line of argument marginalizes offensive wedge drivers by obscuring their ability to act strategically to promote such conºicting views within the polities of their potential adversaries. For recent works in the neoclassical realist school, see Steven E. Lobell, Norrin M. Ripsman, and Jeffrey W. Taliaferro, eds., Neoclassical Realism, the State, and Foreign Policy (Cambridge: Cambridge University Press, 2009). For a neoclassical work that looks at how a state can try to inºuence its adversaries’ domestic political debates over grand strategy, see Steven E. Lobell, “The Second Face of Security: Brit- ain’s ‘Smart’ Appeasement Policy towards Japan and Germany,” International Relations of the Asia- Paciªc, Vol. 7, No. 1 (January 2007), pp. 73–98. 85. Kaufman, Little, and Wohlforth, The Balance of Power in World History. 86. Hui writes, “The inherently weak balance of power mechanism can be further weakened by the divide-and-conquer strategy.” Hui, War and State Formation in Ancient China and Early Modern Europe, p. 27. She continues, “The logic of domination is naturally advantaged over the logic of balancing. Because the balance-of-power mechanism involves the daunting collective action problem, it is quite questionable whether targets of domination can pursue effective balancing.” Ibid., pp. 33–34. See also Victoria Tin-bor Hui, “The Triumph of Domination in the Ancient Chinese Sys- tem,” in Kaufman, Little, and Wohlforth, The Balance of Power in World History, pp. 122–148; and Stuart J. Kaufman, Richard Little, and William C. Wohlforth, “Introduction: Balance and Hierarchy in International Systems,” and “Conclusion: Theoretical Insights from the Study of World Poli- tics,” both in Kaufman, Little, and Wohlforth, The Balance of Power in World History, pp. 14, 19, 129.

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bribes and special concessions. Similarly, Richard Rosecrance and Chih-Cheng Lo argue that Napoleon’s domination of Europe from 1798 to 1813, and the re- peated failure of coalitions to balance against France during this period, in large part resulted from “an obvious collective action problem,” which was ac- centuated by Napoleon’s bullying and bribes.87 Yet, in these accounts, the divider is in a sense cutting through warm butter; many strong antibalancing dynamics are already at work. Offensive wedge strategies are thus theorized a priori as reinforcing rather than countervailing inºuences. If, however, balancing failures are largely overdetermined in this way, these offensive wedge strategies are not very interesting; they are, if not epiphenomenal, marginally inºuential. If the forces favoring disunited and desultory resistance are so strong, why are clever strategies, side payments, and compensations necessary? I argue that expansionists can cause balancing failures by adopting countervailing wedge strategies; using selective accommodation, they can divide counterbalancing alliances that would otherwise form. Two propositions fol- low from this general thesis. First, when balancing alliances fail to form against a threatening power that did not try to divide the blockers through selective accommodation, the prime cause of this failure is likely to be collective action pathologies or perhaps domestic-level factors. Second, when balancing alliances fail to form against a threatening power that seeks to divide the blockers through selective accommodation, and they divide in ways congruent with that strategy, then the expansionist’s policy explains the balancing failure. If, in the second instance, selective accommodation seems to reinforce larger collective action pathologies, the following counterfactual question should be answered through careful qualitative analysis: Would external balancing have failed if the threatening power had not tried to divide the balancers through selective accommodation and instead had confronted them all? The collective action explanation is compelling if a convincing case can be made that the balancers would have remained disunited even if the aggressor had confronted them simultaneously. If, however, the evidence suggests that the balancers would have come together in those circumstances, the expansionist’s wedge strategy is the driver of balancing failure. This analytical approach casts light on what otherwise appears to be the

87. According to Rosecrance and Lo, “‘free riding’ should be the characteristic practice, not the ex- ception to the rule.” They continue, “The game is Prisoner’s Dilemma, which is the typical collective goods game [where] the rational result is for the balancers to disagree. This loads the dice in favor of the threatening aggressor.” Rosecrance and Lo, “Balancing, Stability, and War,” pp. 480– 481 nn. 2, 3.

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worst buck-passing ªasco of the late 1930s: the failure to form an Anglo- Franco-Soviet alliance in August 1939. Hitler’s decision to pursue selective accommodation was the prime cause of balancing failure at that most crucial juncture. The secret German diplomatic campaign for a sweeping accommodation with the Soviet Union bore fruit in a stunning reversal by demolishing the Anglo-Franco-Soviet alliance negotiations, which were then at an advanced stage, and ushering in the Nazi-Soviet pact. Here, Hitler led rather than followed the buck-passing.88 Making this claim explicitly is important, because many interpretations of the Nazi-Soviet pact’s origins put so much blame on the Western allies’ foot- dragging (or Soviet double-dealing) that they treat what was an unlikely German diplomatic coup as if it were a given.89 If the hesitancy of Britain and France to fulªll Soviet requests encouraged Stalin to turn to Hitler, it is none- theless remarkable that the Soviet leader would have had that choice in the ªrst place.90 It is also crucial to bear in mind that Hitler’s bids would inºuence whether the Western powers’ alliance terms were acceptable to Moscow. In addition, it is important not to conºate the situation in 1938 and early 1939— when Britain and France were not serious about an alliance with the Soviet Union—with the situation between May and August 1939. The latter period is the crucial juncture: the German threat to Poland and elsewhere to the east was spiking, which is when one would most expect external balancing to manifest in the consolidation of an Anglo-Franco-Soviet alliance. By the end of May, the British government had set aside its ideological qualms about forming an alliance with the Soviet Union, as well as its mistaken view that Soviet military capabilities were too dubious to be worth pursuing.91 The British cabi-

88. Christensen and Snyder suggest that “Hitler’s strategy in the late 1930s” of “lightning cam- paigns against diplomatically isolated victims” is explained by “the buck-passing [diplomacy] of his opponents,” which “meant that the easier, piecemeal route was available, so Hitler took it.” Christensen and Snyder, “Chain Gangs and Passed Bucks,” pp. 156–157. 89. For recent examples, see Louise Grace Shaw, The British Political Elite and the Soviet Union, 1937–1939 (New York: Routledge, 2003); Michael Jabara Carley, 1939: The Alliance That Never Was and the Coming of World War II (Chicago: Ivan Dee, 1999); and G. Bruce Strang, “The Spirit of Ulys- ses? Ideology and British Appeasement in the 1930s,” Diplomacy and Statecraft, Vol. 19, No. 3 (Sep- tember 2008), pp. 513–514. 90. In the terminology of Kaufman, Little, and Wohlforth, the Soviet Union was induced by Ger- many to “boondoggle” instead of balance (or in Schweller’s terms, “bandwagon for proªt”). The point is that the Soviet grab for gains was brought about by a bargain initiated and elaborated by Germany, for the express purpose of detaching the Soviet Union from an alliance with Britain and France. On boondoggles, see Kaufman, Little, and Wohlforth, Balance of Power in World History, pp. 14, 238–240. On bandwagoning for proªt, see Schweller, Deadly Imbalances, pp. 76–78, 191. 91. Keith Neilson, Britain, Soviet Russia, and the Collapse of the Versailles Order, 1919–1939 (Cam- bridge: Cambridge University Press, 2005), pp. 292–295; and Robert Manne, “The British Decision

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net took a clear decision to engage in a formal alliance with the Soviet Union and to work out joint war plans, and it made important concessions to Soviet demands in the political negotiations so as to move the talks forward to speciªc military questions. By this point, Stalin had seized control of Soviet foreign policy—not to divorce it from the Western alliance track, but to impose a disciplined insistence on Soviet interests in the talks, while retaining the option of dealing with Germany, if that option became both credible and suf- ªciently attractive.92 Although historians disagree about much of Soviet decisionmaking at this time, one point seems clear: Moscow was serious about forming a blocking alliance with Britain and France against Germany, as long as the option of major accommodation with Germany seemed remote or im- plausible.93 Not until mid-August 1939 did increasing German offers of generous compensation to Moscow achieve real traction.94 By then, Stalin was “in the relatively fortunate position of being able to choose between two articu-

for Alliance with Russia, May 1939,” Journal of Contemporary History, Vol. 9, No. 3 (July 1974), pp. 22–23. 92. Silvio Pons, Stalin and the Inevitable War, 1936–1941 (London: Routledge, 2002), p. 158; and Al- bert Resis, “The Fall of Litvinov: Harbinger of the German-Soviet Non-aggression Pact,” Europe- Asia Studies, Vol. 52, No. 1 (January 2000), pp. 46–51. 93. As Jonathan Haslam puts it, given the record of “the Hitler regime’s overt hostility . . . Stalin had no alternative” to the collective security option of western alliance, “until Hitler reversed his line against Moscow.” Haslam, “Soviet-German Relations and the Origins of the Second World War: The Jury Is Still Out,” Journal of Modern History, Vol. 69, No. 4 (December 1997), p. 787. Robert Manne writes: “Even if Stalin had throughout 1939 preferred a Nazi-Soviet pact to alliance with the west it would not have been possible to cease taking the negotiations with the west seriously until assured that Hitler wanted a pact with Russia. . . . German documents suggest that no such assurance could have been gained before August 1939 and perhaps even before mid-August.” Manne, “Some British Light on the Nazi-Soviet Pact,” European History Quarterly, Vol. 11, No. 1 (January 1981), p. 97. 94. Geoffrey Roberts writes, “The story of Soviet-German relations between May and August 1939 is one of persistent wooing by Berlin.” Roberts, The Soviet Union and the Origins of the Second World War (New York: St. Martin’s, 1995), pp. 72–73. See also Roberts, Stalin’s Wars, p. 32. D.C. Watt comments, “What made the [Nazi-Soviet pact] so unique was that its conclusion was from the Soviet viewpoint not a Soviet concession of Danegeld to Germany but a German offer to the Soviet Union, concluded at German initiative.” Watt, “The Initiation of the Negotiations Leading to the Nazi-Soviet Pact,” in Chimen Abramsky, assisted by Beryl Williams, eds., Essays in Honour of E.H. Carr (London: Macmillan, 1974), p. 158. Jonathan Haslam sees Germany during this period pursuing the Soviet Union “with an eagerness bordering on desperation.” Haslam, The Soviet Union and the Struggle for Collective Security in Europe, 1933–39 (New York: St. Martin’s, 1984), pp. 225–226. Ingeborg Fleischauser writes, “Up to...15August 1939, it cannot be said that the Soviet negotia- tors made a real attempt to agree to the German offers. The talks had been characterized by a one- sidedness which frustrated the Germans.” Fleischauser, “Soviet Foreign Policy and the Origins of the Hitler-Stalin Pact,” in Bernd Wegner, ed., From Peace to War: Germany, Soviet Russia, and the World, 1939–1941 (New York: Berghann, 1997), p. 36. Gerald L. Weinberg remarks, “In his eagerness for a war on Poland, Hitler had been willing to make the most extensive concessions to the Soviet Union; more even than Stalin thought to ask for.” Weinberg, The Foreign Policy of Hitler’s Germany, Vol. 2: Starting World War II, 1937–1939 (Chicago: University of Chicago Press, 1980), p. 629.

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lated offers,” one from London and Paris and one from Berlin.95 Only then did Moscow drop the blocking alliance option in favor of a bargain with Berlin. To return then to the counterfactual: if Hitler had not relentlessly pursued a strategy of selective accommodation with Moscow, then Britain, France, and the Soviet Union would very likely have formed an alliance in August 1939— despite their doubts about one another’s resolve, capabilities, and buck- passing tendencies, as well as the obstinacy of Poland and Romania.96 If, during the Polish crisis, Hitler had tried to bully rather than bribe the Soviets into acquiescing, this almost certainly would have negated the collective action problem and solidiªed the Anglo-Franco-Soviet pact that was then in the making. And it was the likelihood and danger to Germany of that counterbalancing alliance that spurred Hitler to such lengths to prevent it. The Nazi-Soviet pact and my counterfactual argument underscore the following essential theoretical points. Only against the backdrop of strong forces of external balancing will offensive wedge strategies have signiªcant effects in international politics. In a world dominated by chronic collective action failures, it is hard not to divide adversaries, and costly efforts should not be necessary. In a world where balancing is potent and prevalent, efforts to block expansionist powers will vary depending on whether and to what extent those powers engage in selective accommodation. These powers may have an advantage when it comes to using inducements to divide their adversaries; their intentions and capabilities to disrupt the status quo may enable them to neutralize blockers with offers of compensation sweetened by gains from their aggression. Such offers may appeal not only to other revisionists but even to states that would prefer the status quo, but wish to beneªt from its breakdown if a breakdown seems inevitable.97 It is costly, however, to make such offers both credible and attractive enough that targets will bite. Several implications for contemporary foreign policy ºow from the above

95. Manne, “Some British Light on the Nazi-Soviet Pact,” p. 97. 96. For the argument that Stalin bandwagoned with Hitler because he doubted Anglo-French capabilities and resolve to confront Germany, see Mark R. Brawley, “Neoclassical Realism and Stra- tegic Calculations: Explaining Divergent British, French, and Soviet Strategies toward Germany between the World Wars (1919–1939),” in Lobell, Ripsman, and Taliaferro, Neoclassical Realism, the State, and Foreign Policy, p. 94. For the claim that Stalin engaged in buck-passing because he overes- timated the ability of Britain and France to resist German power, see Christensen and Snyder, “Chain Gangs and Passed Bucks,” p. 159; Schweller, Deadly Imbalances, p. 166; Thomas J. Christensen, “Perceptions and Alliances in Europe, 1865–1940,” International Organization, Vol. 51, No. 1 (Winter 1997), p. 91; and Walt, “Alliances, Threats, and U.S. Grand Strategy,” p. 458. 97. For the argument that expansionists will be better able to divide a balancing coalition that in- cludes revisionist elements, because those elements can be bought off with prospective gains from aggression, see Schweller, Deadly Imbalances, p. 139.

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discussion. The ªrst implication concerns whether and how U.S. alliances in Asia may be picked apart by a rising China. Here, it is important to look at China’s capacity to use selective accommodation strategies, as well as the growth of its military might.98 It is doubtful, for example, that if U.S.-China tensions spiked, China could use threats to weaken the deepening ties between the United States and India. A timely willingness by Beijing to revisit unresolved border questions with Delhi, however, could have more impact.99 Although Chinese attempts to intimidate South Korea into downgrading its alliance with the United States would almost certainly backªre, Beijing’s willingness to take steps to address Seoul’s security concerns vis-à-vis North Korea, or for that matter Japan, could produce this result indirectly. A China increasingly asserting its power in the region need not blow cold on its neighbors simultaneously. Any assessment of whether China can divide U.S. alliances in Asia must consider its ability to manipulate inducements that are both speciªc and important to local actors, as well as uniquely under its control. Second, the potential for regional expansionists to use offensive wedge strategies sheds light on the argument that the United States should adopt an “offshore balancing” grand strategy. The ªrst theoretical plank in the offshore balancing argument is that an insular power such as the United States need not be forward deployed to prevent the rise of rivals in other regions (such as Europe or Asia), because local actors will ªnd it in their own interests to balance against rising rivals.100 “It’s money in the bank,” writes Christopher Layne, “that some of them will step up to the plate and balance against a powerful, expansionist state in their own neighborhood.” Indeed, Layne argues, the aloof behavior of the offshore balancer “compels others to take on the risks and costs of counter-hegemonic balancing.”101 The countervailing potential of offensive wedge strategies, however—their ability to neutralize would-be regional balancers—calls into question the strong presumption of automaticity implied in such arguments.102 With the presumption in favor of local balancing

98. Michael Glosny, “Access to U.S. Bases in Japan and the Defense of Taiwan: The Susceptibility of the U.S.-Japan Alliance to Chinese Wedge Strategies,” paper prepared for the annual meeting of the American Political Science Association, Chicago, Illinois, August 29–September 2, 2007; and Thomas J. Christensen, “Posing Problems without Catching Up: China’s Rise and Challenges for U.S. Security Policy,” International Security, Vol. 25, No. 4 (Spring 2001), p. 11. 99. On these disputes, see Edward Wong, “Uneasy Engagement: China and India Dispute Enclave on Edge of Tibet,” New York Times, September 3, 2009. 100. For this view, see Christopher Layne, The Peace of Illusions: American Grand Strategy from 1940 to the Present (Ithaca, N.Y.: Cornell University Press, 2006), chap. 8; and John J. Mearsheimer, “Im- perial by Design,” National Interest, No. 111 (January/February 2011), pp. 18, 33. 101. Layne, The Peace of Illusions, pp. 181–182. 102. For Christopher Layne’s response to this point, see Layne, “America’s Middle East Grand

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thus compromised, the weight of the argument for offshore balancing falls on the second, more pragmatic wait-and-see principle: even if local balancing fails, the offshore power can afford to stand back, conserve its resources, and pick the best time and side on which to intervene. This may be true, but if local balancing fails badly and quickly, the option to choose sides later may be dras- tically diminished. There is thus an important contingency to prescriptions for an offshore balancing policy. The approach will work better against regional expansionists that lack the resources or aptitude for selective accommodation than against those that have them and use them.

Conclusion

In this article, I presented several concepts and propositions that inform scholarly analysis of how and when wedge strategies work. First, I described the differences between reinforcing and countervailing strategies. Any serious attempt to investigate and theorize about the role of wedge strategies in international politics must acknowledge that wedge strategies can be used—and can succeed—against adversaries that are hard to divide as well as those that are easy to divide. The critical issue for research on wedge strategies concerns countervailing attempts and their logic and conditions for success. Second, I distinguished between two broad approaches to dividing adversaries—selective accommodation and confrontation—and argued that for countervailing purposes, states are more likely to use selective accommodation strategies, which are more likely to succeed than confrontation strategies. Third, I argued that two cost considerations shape how and when selective accommodation works: the costs to the target of different degrees of alignment change, and the costs to the divider of different ways to induce that change. The selective accommodation attempts that work best and matter most capitalize on the divider’s secondary interests to induce potential adversaries to become or remain neutrals. Regarding their implications for power politics, I argued that defensive wedge strategies are an important form of external balancing, one that can substitute for building arms and alliances. The harder it is for states to build arms and recruit allies to meet a composite threat, the more they will try to weaken and isolate the main threat by neutralizing lesser ones. I also argued that offensive selective accommodation strategies are a primary prior cause of

Strategy after Iraq: The Moment for Offshore Balancing Has Arrived,” Review of International Studies, Vol. 35, No. 1 (January 2009), p. 10.

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balancing failures; they prompt the buck-passing, bandwagoning, and distancing behavior that prevents counterbalancing alliances from forming that otherwise should. These two arguments point to two additional propositions that should encourage scholars to think more about how and when wedge strategies work. Each responds, in part, to the growing view that balancing is not, or is no longer, a signiªcant force in world politics. Each also suggests important lines of inquiry for further study of wedge strategies. First, that external balancing sometimes fails in situations where the formation of robust counteralliances ought to be expected does not mean that balancing is a weak force in international politics. Leaders are usually cognizant of the potential for counterbalancing and look out for it. When the conditions for counterbalancing are propitious, some expansionists will accept stasis. Jack Levy refers to this situation as “unobserved balancing...theabsence of war . . . due to the anticipation of balancing by the potential aggressor.”103 Other expansionists will engage in rapid self-encirclement.104 Still others will try to divide the balancers through selective accommodation; and the more likely and dangerous the coalition, the harder they will try. Sometimes these latter expansionists will succeed. When they do, it is not because the balancing dynamic is weak, but because its strength spurred them to make commensurate efforts to overcome it. In short, just because some states overcome balancing does not mean that it is easy to do so. One way for scholars to assess whether or not it was easy for an offensive divider to thwart counterbalancing is to look at the level of effort and cost it expended to do so. If cheap talk and superªcial endorsements were all that was required, then the balancing dynamic was anemic. By contrast, if an offensive divider traded important interests and values to bring about the destruction of a blocking coalition, then the balancing dynamic was more robust. Second, if the major function of defensive wedge strategies is to neutralize or disalign an expansionist’s allies, another kind of successful but unobserved balancing can result. Moral hazard makes aggressors more prone to adventur- ism and escalation when they are backed, or expect to be backed, by allies that will absorb some of the costs.105 By detaching or distancing a potential aggres-

103. Levy, “Balances and Balancing: Concepts, Propositions, and Research Designs,” p. 138. 104. Colin Elman, “Introduction: Appraising Balance of Power Theory,” in Vasquez and Elman, Realism and the Balancing of Power, pp. 11–12. 105. See Timothy W. Crawford, “The Endurance of Extended Deterrence: Continuity, Change, and Complexity in Theory and Policy,” in T.V. Paul, Patrick M. Morgan, and James J. Wirtz, eds., Com- plex Deterrence: Strategy in the Global Age (Chicago: University of Chicago Press, 2009), pp. 291–294; and Snyder, Alliance Politics, p. 44.

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sor’s allies, then, a divider can increase the opponent’s expected costs of ªghting and thus deter it. It is hard to observe this sort of balancing effect, especially if it makes an aggressor scale back but not forgo aggression. But common sense and the logic of moral hazard suggest that such effects are widespread and that many status quo states have beneªted from them. This understanding of the impact of defensive wedge strategies in power politics adds to the deductive case for balancing as a common and signiªcant force in international politics. But there is more to be done: students of power politics should devise ways to investigate whether and how these hard-to-observe mechanisms operate in speciªc cases. One way to begin is to search the war plans, strategic discourse, and diplomacy of expansionists that have suffered the loss of an ally (or allies) through the process of detachment for changes consistent (or not) with the restraining effect expected of defensive wedge strategies. A better understanding of how and when wedge strategies work underscores three truths of power politics that scholars should keep in mind. First, the pursuit of relative power is as much about subtracting and dividing as about adding and multiplying. Second, neutral countries can matter a great deal for the strength and security of other states. A critical component of states’ strategic behavior comprises efforts to create neutral countries or deny their capabilities to others. Third, dividing adversaries is not always easy, and when it is hard, wedge strategies matter most. This is why selective accommodation wedge strategies are important. Leaders who assume that division is easy are liable to forgo selective accommodation and confront too many potential adversaries simultaneously, compounding the encirclement of their states.

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