The Influence of Seapower on Politics: Domain- and Platform-Specific Attributes of Material Capabilities Erik Gartzke Jon R. Lindsay 26 May 2020 Accepted for publication in Security Studies. Final copyedited text may differ. Please consult published version for citation. Wordcount: 12,974 (abstract 194) Abstract: Students of world politics have long shown a special interest in seapower. International relations, however, tends to treat the means of power as homogeneous and interchangeable. Are military capabilities largely undifferentiated goods, or do specific assets matter for politics? We argue that the characteristics of naval power offer distinctive tradeoffs in terms of the causes of war. Naval presence, firepower, and mobility enable naval nations to fight farther from home and obtain more diplomatic recognition. At the same time, mobility and stealth introduce ambiguity about national priorities and contribute to errors in assessing the local balance of power and resolve. We find empirically that disproportionate investment in seapower is associated not only with heightened diplomatic recognition and power projection across greater distances, but also with increased instability in the form of a higher risk of dispute initiation. Disaggregating seapower by platform type— battleships, submarines, aircraft carrier—reveals similar tradeoffs across platforms as for naval power generally. Navies empower political leaders to intervene in distant locales, where their interests are more peripheral, and to reconsider their commitments, where their interests do not justify the risk. This suggests that “offshore balancing” strategies may, counterintuitively, be destabilizing. Keywords: seapower, maritime strategy, force structure, strategic stability, political influence Authors: Erik Gartzke ([email protected]) is Professor of Political Science at the University of California, San Diego and Director of the Center for Peace and Security Studies (cPASS). Jon R. Lindsay ([email protected]) is Assistant Professor at the Munk School of Global Affairs and Public Policy at the University of Toronto. Acknowledgements: This research was supported by the Department of Defense Minerva Initiative (Office of Naval Research Grant N00014-14-1-0071). The authors are indebted to Rex Douglass and Thomas L. Scherer for assistance with data analysis. This paper has benefited from generous feedback at workshops and conferences too numerous to list, as well as thoughtful anonymous reviewers. Lauren Gilbert provided valuable research assistance. Introduction Thucydides credits Pericles with the argument that seapower enabled Athens to offset Spartan military prowess: “For our naval skill is of more use to us for service on land, than their military skill for service at sea.”1 Pericles offers four reasons for his claim. First, commercial wealth and offshore holdings enabled Athens to prosecute a long war, while Sparta had to conclude wars quickly to protect its agriculture: “the desolation of the whole of Attica is not the same as that of even a fraction of Peloponnese; for they will not be able to supply the deficiency except by a battle, while we have plenty of land both on the islands and the continent.”2 Second, Spartan land victories could not prevent Athens from imposing costs by sea: “a mere post might be able to do some harm to the country by incursions and by the facilities which it would afford for desertion, but can never prevent our sailing into their country and raising fortifications there, and making reprisals with our powerful fleet.”3 Third, high barriers to maritime competence prevented Sparta from mounting a serious naval challenge: “the restraint of a strong force will prevent their moving, and through want of practice they will grow more clumsy, and consequently more timid.”4 Fourth, sea control offered Athens an “impregnable position” safe from “battle with the numerical superiority of the Peloponnesians.”5 In short, the dispersion, mobility, and capability of its fleet expanded strategic options for Athens relative to Sparta. As Pericles summarizes, “The rule of the sea is indeed a great matter”6 Yet the international relations field tends to treat material capabilities as undifferentiated goods. 1 Thucydides, The History of the Peloponnesian War, trans. Richard Crawley (New York: E. P. Dutton, 1910), 1.142.5. 2 Thucydides, 1.143.4. 3 Thucydides, 1.142.4. 4 Thucydides, 1.142.8. 5 Thucydides, 1.143.5. 6 Thucydides, 1.143.5. See also Joshua Rovner, “Sea Power Versus Land Power—Cross-Domain Deterrence in the Peloponnesian War,” in Cross-Domain Deterrence: Strategy in an Era of Complexity, ed. Jon R. Lindsay and Erik Gartzke (New York: Oxford University Press, 2019), 163–85. Rovner argues that Athens and Sparta each used their domain-specific advantages to discourage war, but shifting alliances muddied perceptions of the balance of power. Ironically, their respective advantages then prolonged the contest because both nations were deterred from engaging in decisive offensive operations in their opponent’s favored domain. 2 Work on deterrence, coercion, and war often considers military capabilities as raw inputs to national power that do not merit careful assessment because they are not subject to strategic interaction, are equivalent in their effects, or both. While policymakers and military commanders may fret about the details of force structure and the minutia of acquisitions and arms control agreements, these are often considered mere technical problems in the implementation of aggregate military power. At the same time, students of international politics have also had an enduring interest in how nations use the maritime domain and what offshore power means for foreign affairs, fashioning influence, projecting power, or deterring aggression. This preoccupation with the strategic features of the maritime domain is presumably unnecessary if details of the production and exercise of power are both ubiquitous and indistinct. Is seapower a specific asset with distinct political advantages and liabilities, or are the means of war politically fungible? We offer an argument and evidence about the distinct influence of seapower on international politics. We build on the common assumption that strategy is a relationship between political ends and military means.7 Yet political actors have many ends and many means. Military force can be used for distinct political objectives such as protecting or revising the status quo, deterring potential aggressors, or reassuring allies.8 Politicians and commanders can also choose from a growing portfolio of different forces in different operational domains (land, sea, air, space, cyberspace), each more or less suitable for enhancing the credibility, effectiveness, or efficiency of national policy.9 One of the defining characteristics of seapower is its special role in projecting power. Navies enable countries to influence politics in more places, more decisively, farther from home. At the same time, however, the heightened mobility and stealth of warships and submarines create ambiguity about where, and for how long, naval 7 Inter alia, Barry R. Posen, The Sources of Military Doctrine: France, Britain, and Germany between the World Wars (Ithaca, NY: Cornell University Press, 1984), 13; Richard K. Betts, “Is Strategy an Illusion?,” International Security 25, no. 2 (2000): 5–50. 8 Robert J. Art, “To What Ends Military Power?,” International Security 4, no. 4 (1980): 3–35, https://doi.org/10.2307/2626666. 9 Jon R. Lindsay and Erik Gartzke, “Politics by Many Other Means: The Comparative Strategic Advantages of Operational Domains,” Journal of Strategic Studies, Forthcoming. 3 power will be concentrated. This creates uncertainty for political actors that undermines signals of commitment, which increases the risk of conflict. The operational characteristics of seapower have two important strategic implications. First, naval nations are tempted intervene in more places, especially where seapower can be used to create locally favorable concentrations of power. Second, it is not clear whether they will intervene in any given place, especially where there is a heightened risk of losing the fleet. While proponents of “offshore balancing” strategies expect navies to bolster deterrence,10 seapower may in fact undermine strategic stability. We find empirically that countries with disproportionately large navies, controlling for military spending, tend to receive more diplomatic recognition and project power further from home.11 This in itself is not surprising, but it is helpful to validate navalist expectations.12 Yet maritime nations also tend to be involved in more militarized disputes, which runs counter to conventional wisdom about the stabilizing influence of seapower. We also extend the process of disaggregating capabilities to assess heterogeneous effects on the scope and scale of influence and stability to specific naval platforms. Ship classes differ in their ability to improve military effectiveness or provide credible signals of intent. Submarines—emblematic of stealth—should be better at projecting power than exerting influence, also leading to increased uncertainty about the intensity or permanence of national interests. Aircraft carriers are considered to be especially good at providing “presence”—Huntington Ingalls Industries thus describes the USS Gerald R. Ford as “100,000 tons of diplomacy.” Yet aircraft carriers may or may not do more for power projection than other types of warships,