CHAPTER 7 A Punctuated Equilibrium Model of Enduring Rivalries Our project consists of two connected parts, the ®rst is a new way of think- ing about international con¯ictÐthe rivalry approach; the second involves exploring an important class of con¯ict phenomena suggested by the rivalry approachÐenduring rivalries. In part 1, we focused on the rivalry approach by de®ning the core concept of international militarized rivalry and then looking at the theoretical and methodological implications of investigating international con¯ict phenomena using this theoretical framework. We found that the rivalry approach had major implications for thinking about and conducting research on questions of deterrence, crisis behavior, the democratic peace, and other aspects of war and peace. In this second part of the book, we concentrate our efforts on enduring ri- valries as empirical phenomena. The empirical patterns noted in chapter 3 indi- cate that enduring rivalries encompass a large portion (in some cases a majority) of the most violent international con¯ict over the past two centuries. Thus, in some sense, understanding enduring rivalries becomes a central component of understanding international con¯ict in general. Furthermore, to the extent that policy relevant guidelines can be derived from analyses of international con- ¯ict, those that help ameliorate the most deleterious aspects of enduring rival- ries must have the highest priority on any research agenda. Until recently enduring rivalries as con¯ict phenomena have escaped study by students of international war. The ®rst part of this book showed that the ri- valry approach sheds new light on many theories of war. Now, we argue that one needs a model of enduring rivalries. By replacing ªwarº with ªenduring rivalry,º we fundamentally change the research and theoretical enterprise. For the last 30 years con¯ict research has used war or dispute occurrence as the consensus dependent variable. With the rivalry approach, we suggest that other aspects of international and militarized con¯ict deserve attention. When we move to enduring rivalries as the focus, 131 132 A Punctuated Equilibrium Model of Enduring Rivalries we no longer have just one dependent variable, but multiple ones. Using the life-cycle metaphor, we ®nd that there are three major categories of dependent variables. The ®rst involves (enduring) rivalry birth. Here the two key ques- tions are ªwhy do rivalries start?º and ªwhy do some rivalries become endur- ing?º Symmetrically, a second class of questions inquires about enduring ri- valry termination and con¯ict resolution: why and when do enduring rivalries end? The third, large and heterogeneous, class consists of questions about the growth, development, and evolution of enduring rivalries. We examine aspects of those three dimensions of the enduring rivalry life- cycle. Although we present more speci®c hypotheses about the beginning, evo- lution, and termination of enduring rivalries, we do so within a general model that encompasses all three and what we call the punctuated equilibrium model of enduring rivalries. We use the punctuated equilibrium label because our model shares many characteristics with the biological theory of punctuated equilibrium. The biological theory stresses the very uneven rates of species evolution, arguing that it occurs in spurts followed by long periods of stasis and no change. Species evolve rapidly, change little, and then go extinct quickly. This, we will argue, is the dominant pattern in enduring rivalries. States rapidly lock-in to enduring rivalries, which then change little until their rapid demise. In the second half of this book, we propose the punctuated equilibrium model of enduring rivalries and use it as a guide to analyze several aspects of enduring rivalries. In adopting this biological framework, we borrow from the models that have revolutionized the study of evolutionary biology over the past several decades, but we also pro®t from the insights gained by using such mod- els to understand political phenomena, mostly notably studies of public pol- icy formation in the United States. Our contention is not that biological sys- tems are identical to those occasioned by enduring rivalries, but rather that the punctuated equilibrium model in biology offers a useful and heuristic analogy by which to understand the dynamics of enduring rivalries. In describing this model, we begin by brie¯y discussing the biological aspects of the punctuated equilibrium modelÐparticularly those of relevance to usÐand then move to discuss its application to public policymaking. With this groundwork, we then discuss its general application to enduring rivalries. We leave speci®c appli- cations, hypotheses, and empirical analyses to the four substantive chapters in this part of the book. The Punctuated Equilibrium Model and Its Biological Origins For decadesÐsince the 1940sÐwhat Julian Huxley identi®ed as ªthe mod- ern synthesisº dominated the thinking of evolutionary biologists. Prior to this synthesis, a ªbewildering array of evolutionary process theories existed, each touted by a different biological discipline seemingly bent upon establishing the primacy of its own phenomena and its own insightsº (Eldredge 1985, 3). The The Punctuated Equilibrium Model and Its Biological Origins 133 modern synthesis combined Darwin's theory of natural selection with the dis- covery of how genes produce variation upon which natural selection can work. Perhaps most elegantly summarized by Gould (1983, 13), the synthesis em- phasized ªgradual, adaptive change produced by natural selection acting exclu- sively upon organisms [i.e., not species].º The standard theory thus saw evo- lution occurring everywhere, all the time, and in an incremental fashion. It was from a group of paleontologists outside the core of evolutionary the- ory (often formal and mathematical) that arose the challenge to the gradualist vision of natural selection (see Eldredge 1995 for an account of the admission of paleontologists to the ªhigh tableº of evolutionary theory). The fossil record produces little evidence for the incrementalist position. That is, the literal geo- logical record was more supportive of abrupt changes: most fossil species dis- appear looking much the same as when they appeared, while new species in any local area appear abruptly and fully formed. TraditionallyÐstarting with DarwinÐthis was deemed the result of the rarity and poor quality of the fossil record. In 1972, Eldredge and Gould proposed the punctuated equilibrium model, which instead of explaining away discrepancies between data and the standard theory devised a theory that matched more directly the fossil record (see El- dredge 1995 for a survey and overview). The punctuated equilibrium model portrays evolution as primarily the product of rapid speciation. The model sug- gests a process characterized by long periods of stasis punctuated by the sudden appearance of new, qualitatively different species. Unlike the standard model, the punctuated equilibrium model regards speciation and evolution as rare, oc- curring in speci®c and unusual circumstances. As Gould recounts (1987, 37), scholars working in the modern synthesis only looked for gradualist evolution in choosing their cases for study. ªOver and over again in my career I have bashed my head against this wall of non- reporting [of null results]. When Niles Eldredge and I proposed the theory of punctuated equilibrium in evolution, we did so to grant stasis in phylogenetic lineages the status of worth reportingÐfor stasis had previously been ignored as nonevidence of nonevolution, though all paleontologists knew its high fre- quency.º With the punctuated equilibrium model in hand, biologists began to ªseeº long-term stasis in species as well as periods of rapid speciation. The most novel of the rare speciation propositions was the suggestion that the birth and death of most species occur during periods of major environmental change and shock. The most famous of these is the claim that a large asteroid hit the earth about 60 million years ago, causing the extinction of 65±70 percent of all existing species (Raup 1992). The evolutionary window of opportunity that this event opened resulted in the rise of thousands of new species. The punctuated equilibrium model also stresses that speciation comes about through geographic isolation: ªa small segment of the ancestral popu- lation is isolated at the periphery of the ancestral range. Large, stable central 134 A Punctuated Equilibrium Model of Enduring Rivalries populations exert a strong homogenizing in¯uence. New and favorable muta- tions are diluted by the sheer bulk of the population through which they must be spread. They must build slowly in frequency, but changing environments usu- ally cancel their selective value long before they reach ®xation. ... [Still] small, peripherally isolated groups are cut off from parental stock. They live as tiny populations in geographic corners of the ancestral range. Selective pressures are usually intense because peripheries mark the edge of ecological tolerance for ancestral forms. Favorable variations spread quickly [speciation]. Small, peripheral isolates are a laboratory of evolutionary changeº (Gould 1983, 183± 84). This, however, was already part of the modern synthesis, particularly due to the work of Mayr (1970). Today, almost three decades after it was ®rst in- troduced, the punctuated equilibrium model has been accepted by a majority of evolutionary biologists