«Unfair Fights: Power Asymmetry, Nascent Nuclear Capability, and Preventive Conﬂict Forthcoming in Conﬂict Management and Peace Science Abstract ...»
Unfair Fights: Power Asymmetry, Nascent Nuclear
Capability, and Preventive Conﬂict
Forthcoming in Conﬂict Management and Peace Science
Scholars have long recognized that imminent shifts in relative power may motivate declining
states to initiate conﬂict. But what conditions exacerbate the risk posed by these anticipated
power shifts? Building upon existing bargaining models of war, I show that larger initial power
asymmetries increase the probability of preventive conﬂict. Theoretical extensions that account for certainty effects and variable costs of war, both of which are linked to initial dyadic power balances, drive this relationship. It follows that looming power transitions in which rising states approach and surpass parity, long considered war-prone scenarios, are not particularly problematic. Instead, the risk of conﬂict is greatest when preponderant powers confront conventionally weak but rising states. I test the theoretical predictions in the context of anticipated power shifts due to rivals pursuing nuclear weapons. Extensive empirical tests that relax assumptions employed in prior analyses of preventive conﬂict offer strong support for this contention. These results shed light on the underpinnings of many pressing contemporary interstate security issues.
I do think there’s no doubt about the outcome. There’s no question about who is going to prevail if there is military action. And there’s no question but what it is [sic] going to be cheaper and less costly to do it now than it will be to wait a year or two years or three years until he’s developed even more deadly weapons, perhaps nuclear weapons.
And the consequences then of having to deal with him would be far more costly than will be the circumstances today. Delay does not help.
—Vice President Dick Cheney1 By emphasizing the problem posed by a future shift in relative capabilities, Cheney’s justiﬁcation for the Iraq War highlights a commonly theorized cause of interstate conﬂict. The bargaining theory of war identiﬁes power shifts and the resulting commitment problems as one of the primary rationalist paths toward war (Fearon, 1995; Powell, 2006). The logic is as follows: a rising state cannot credibly commit to a future distribution of a contested resource because its expanded capabilities will enable it to demand a division revised in its favor in later negotiations. The declining state initiates a preventive war before its bargaining leverage is diminished. Scholars of history and international relations have contributed to a voluminous literature exploring the preventive war motivation and its critical role promoting conﬂict stretching from the Peloponnesian War to the 2003 invasion of Iraq (Thucydides, 1935; Taylor, 1954; Levy, 1987; Trachtenberg, 2007; Lake, 2010; Debs and Monteiro, 2014).
This paper asks what conditions exacerbate the risk of power shifts causing preventive conﬂict, with an empirical focus on anticipated power shifts due to nuclear proliferation. Cheney’s justiﬁcation offers a possible answer as he notes the highly asymmetric nature of the opposing sides’ forces and the consequent certainty of US victory. Building upon existing bargaining models of war, I Quoted in a March 16, 2003 interview on NBC News’ Meet the Press (2003).
hypothesize that the starker the initial power disparities, the greater the probability of commitment problems emerging and preventive conﬂict ensuing.2 Prior work on commitment problems examines the size and speed of power shifts and whether states induce power shifts by expanding their arsenals as pivotal factors underpinning bargaining failures (for example, Powell 1999; Bas and Coe 2012). However, the literature generally neglects or argues against the existence of a relationship between initial power balances and the magnitude of shifts in relative power needed to induce conﬂict.3 In contrast to past work, I introduce two extensions to a canonical bargaining model that show that initial power asymmetries have important implications for preventive conﬂict. A ﬁrst addition introduces certainty effects to the decision process (Allais, 1953; Tversky and Kahneman, 1979; Andreoni and Spenger, 2012). With a preference for certainty, leaders of states with large power advantages and high certainty of victory in preventive conﬂict are particularly sensitive to adverse shifts that would introduce greater uncertainty over conﬂict’s outcome. Consequently, for an anticipated power shift of a given size, the probability of preventive conﬂict is higher in these asymmetric dyads than in dyads near parity. The second addition incorporates variable costs of war under the assumption that ﬁghting a weak adversary is less costly than ﬁghting a strong one.
Adverse power shifts increase a declining state’s future costs of war, making subsequent bargaining interactions less attractive. As I expand upon later, because these marginal cost increases are greatest for preponderant powers in decline, preventive war is most attractive in these asymmetric dyads. A model with these extensions reveals there is nothing particularly dangerous about balTo be clear, initial refers to the capability distribution before the anticipated power shift occurs. I use asymmetry and disparity to reference dyads in which the declining state enjoys a large initial power advantage whereas parity refers to dyads in which states are initially relatively equal in capabilities. A power shift refers to an anticipated change in relative dyadic capabilities and can occur across the full range of initial capability distributions. That is, power shifts are possible where the declining state is already the weaker party, is near parity (in which case a transition may occur), or is the stronger party with an asymmetric advantage.
Debs and Monteiro (2014) is a partial exception discussed in the next section.
anced dyads with looming power transitions in which a rising state’s capabilities will surpass those of a declining state. In fact, the opposite is true. Growth in a weaker state’s capabilities is more likely to induce intractable commitment problems in highly unbalanced dyads.
Empirical tests show this hypothesis is not merely a modeling curiosity. Unlike much of the recent theoretical work on commitment problems, I conduct extensive quantitative tests that evaluate the effect of relative power endowments on the probability of preventive conﬂict and ﬁnd strong support for the overall contention.
Multiple pathways can generate anticipated power shifts. A state’s rise could be due to rapid economic growth, a population boom, large military mobilization programs, resource discoveries, or technological breakthroughs. Unfortunately, quantitative tests of preventive motives are problematic because future power shifts are often difﬁcult to systematically identify ex ante. To overcome this difﬁculty, I analyze instances where a state confronted a rival with a nuclear weapons program. A technological breakthrough of this magnitude presents a scenario with the stark possibility of a change in relative capabilities. As compared to alternative sources of power shifts, nuclear weapons programs are especially likely to induce preventive reasoning by rivals and are comparatively clear for researchers to identify ex ante. The empirical tests and robustness checks support the model’s predictions in the speciﬁc context of nuclear proliferation programs.
In addition to furthering our understanding of commitment problems, the ﬁndings contribute to work identifying rational factors promoting asymmetric conﬂict (Sechser, 2010; Allen and Fordham, 2011). Elevated risks of commitment problems in asymmetric dyads offer one explanation as to why states ﬁght when the outcome is nearly a foregone conclusion. Consider the Iraq War.
A number of valuable studies highlight domestic factors that contributed to the invasion (Monten, 2005; Shannon and Keller, 2007; Cramer, 2007). I do not dispute the presence or importance of such factors but wish to add another, systematic explanation. According to my hypothesis, US military preeminence ensures many of its dyadic relations are asymmetric and thus prone to commitment problems wherein a weak state expected to gain power cannot make sufﬁcient concessions to offset US concerns about the future. This theoretical contention sheds light on why US concerns about adverse power shifts animate many of the most pressing security debates.
The rest of the paper is organized as follows. The next section surveys the theoretical and empirical literature on preventive war and asymmetric conﬂict. In the following section, I extend a bargaining model to formulate a theory linking initial dyadic power balances to the likelihood of preventive conﬂict and stipulate empirical implications that follow from the model. I then describe the research design, present empirical results, and calculate the substantive effect of power asymmetries. The ﬁnal section concludes.
This study contributes to two literatures of international conﬂict. The ﬁrst concerns power shifts, commitment problems, and preventive war. The majority of existing work concerns the size and rapidity of power shifts while largely ignoring the role of initial relative power endowments. The second addresses causes of asymmetric war. Why does conﬂict occur when there is little doubt about its outcome? I review existing explanations, none of which link asymmetric conﬂict to elevated risks of preventive war as I propose.
Studies of Preventive War
A sizable shift in relative power is arguably the most often invoked cause of war. Taylor (1954) claims, “Every war between Great Powers [in the 1848-1914 period] started as a preventive war, not a war of conquest.”4 It is thus unsurprising that a vast literature on international conﬂict addresses the role of looming changes in power distributions in promoting conﬂict. The bargaining theory of war demonstrates that even with complete information, rational states can fail to achieve an In a similar vein, Van Evera (1999, ch. 4) offers an extensive list of cases of preventive war stretching from 18th century Europe to the 1973 Yom Kippur War.
accord if there is an impending shift in relative power (Fearon, 1995; Powell, 1999, 2006).5 Recent contributions further this research agenda by making power shifts endogenous. Considerations include shifts generally (Chadefaux, 2011), probabilistic diffusion of new technologies such as nuclear weapons (Bas and Coe, 2012), ﬁghting itself as a means to forestall power changes (Powell, 2012), or imperfect observability of nuclear proliferation (Debs and Monteiro, 2014).
In contrast to the substantial literature addressing the magnitude and timing of power shifts, little work considers what other factors may inﬂuence the likelihood of intractable commitment problems occurring. A few exceptions suggest preventive war is more likely when the offensedefense balance favors offense (Van Evera, 1999), the declining state is non-democratic (Schweller, 1992), or when the future is highly valued relative to the present (Tingley, 2011).
I argue another factor matters; preventive war is more likely when initial power asymmetries are greater. Consequences of the pre-shift power balance have received ﬂeeting attention. Gilpin (1981) argues that radical revision to the status quo is most probable when transitions occur—that is, when a hegemon is overtaken. Rather than delaying conﬂict until equality is achieved, the declining state opts to eliminate the rising challenger while it maintains a military advantage. Levy (1987) suggests that the preventive motive can arise without the prospect of a power transition, noting that the size and speed of change are critical, not transition itself. However, this conjecture stipulates that if the declining state’s initial advantage is enormous, war is unlikely unless there is a stark and discontinuous shift in the dyadic balance of power, such as a rising state’s procurement of weapons of mass destruction.6 In the bargaining theory of war, the symmetry of initial capability endowments and the possibility of a power transition are immaterial to commitment problems emerging. Debs and Monteiro (2014) and Monteiro and Debs (2014) are partial exceptions, positing that preventive war is more likely the larger the net effect of a shift in power on the relative See Gartzke (1999) for a discussion of the viability of commitment problems as a rationalist explanation for war.
Levy (2011) highlights the Israeli strikes on Osirak in 1981 and a Syrian reactor in 2007 as examples of this phenomenon. Lake (2010) suggests US ofﬁcials were partly swayed by similar reasoning in the 2003 Iraq War.
balance of capabilities and the smaller the costs of preventive war. Both of these conditions, though not directly modeled in Debs and Monteiro (2014), are associated with asymmetric dyads. I reach a complementary conclusion while elaborating upon the cost argument and developing an alternative underpinning for the relationship between asymmetry and preventive war.
A litany of quantitative tests have generated little consensus regarding the effect of power shifts on conﬂict onset (Organski and Kugler, 1980; Kim and Morrow, 1992; Bennett and Stam, 2004).
Furthermore, studies often operationalize power shifts in a retrospective manner that provide a test of power transition theories but not of preventive reasoning. That is, the quantity identiﬁed reﬂects whether past shifts, not anticipated shifts, induce conﬂict. The logic of conﬂict in this formulation is one of revision, not prevention. The dearth of quantitative testing of preventive war stems from the difﬁculties of operationalizing when a shift is approaching. Lemke (2003) and Weisiger (2013) provide rigorous expositions of these empirical hurdles and suggest a measure of past shifts can proxy for the presence of a preventive motivation. This proposition requires the assumption that states extrapolate past changes in relative capabilities into the future. Empirical speciﬁcations in this paper do not rely on this assumption, which I address in later sections.
Studies of Asymmetric War