Retrenchment causes nuclear war from prolif and deterrence collapse---the cost of balancing alone spurs unchecked nationalism and guarantees escalation

Libertarians assume that in the absence of an alliance with the United States, other countries would simply increase their defense spending if they felt threatened. However, internal balancing is not a mechanical process. According to John Mearsheimer, leaders of states facing security competition are likely to use nationalism to garner support from their populations for the necessary regeneration of military capabilities.87 Writing at the end of the Cold War, Mearsheimer suggested that Europe would revert to a pattern of recurrent warfare. The absence of the United States and the Soviet Union would leave Europe, once again, an anarchic multipolar system. The structure of the system would force the states to compete with one another, as they had prior to the Cold War. Mearsheimer argued that pre-1945 “hypernationalism” was a product of “security competition among the European states, which compelled elites to mobilize public support for national defense efforts.”88 American retrenchment could similarly lead to an anarchic, multipolar Europe—thus increasing the chances of war on the continent. Such a system could engender nationalist sentiments among the populations of Europe, heightening animosities between national groups. These heightened animosities could help erode norms against military aggression that have facilitated the decline in interstate war. Nationalist groups within a country can seize on these sentiments to pursue confrontational and expansionist policies.89 Encouraging support for increased military capabilities through nationalism might lead populations to see war as once again a means to national glory or maintaining national honor. Matters of national prestige and honor can lead to the initiation of wars when bound up in territorial claims, while at the same time increasing the intensity and duration of a conflict.90 Nationalism and security competition might also erode the pacifying effects of economic openness. Realism suggests states are concerned about relative gains.91 States in security competition might be wary of trading with one another due to concerns about how a potential rival’s economic gains might provide it with an advantage if translated into military power. They may also adopt autarkic policies for fear of undermining their economic and military self-sufficiency.92 Territorial conquest has become increasing anachronistic in international politics. However, the proliferation of protectionist policies might once again make aggression and preventive war seem like strategically sensible ways for states to secure the resources necessary to reduce the ability of potential rivals to cut them off economically. If the risk of territorial aggression increases, the possession of nuclear weapons would become an attractive option for some states whose security was previously guaranteed by the United States. Nuclear weapons are most useful for deterring major territorial aggression, meaning their potential utility increases as the potential for war does.93 A number of U.S. allies have either previously pursued nuclear weapons or have the capability to do so. They might choose to obtain a nuclear arsenal once responsible for their own security. There are at least two reasons why increasing the number of nuclear weapons states may not have the pacifying effect some realists suggest they do. First, states do not always adopt the second-strike—that is, retaliatory—postures realists assume they will. Recent research shows that even in the paradigmatic case of mutual assured destruction—the Cold War superpower standoff—neither the United States nor the Soviet Union abandoned the search for a first-strike capability.94 Moreover, political scientist Vipin Narang’s research on India-Pakistan nuclear relations has demonstrated that states sometimes adopt risky postures in pursuit of goals other than deterrence.95 Second, an increased number of nuclear weapon states will increase the chances nuclear weapons will be used even if states do adopt second-strike postures. On the one hand, simple organizational pathologies or political instability in a new nuclear state could lead to an accidental or unauthorized nuclear launch.96 On the other hand, even for retaliatory postures, effective deterrence requires that states credibly signal that they are willing to use nuclear weapons in retaliation for an attack. To do so requires that nuclear states in competition with one another must maintain a willingness to risk nuclear war. The greater the number of these “competition[s] in risk taking,” as Thomas Schelling called them, the more likely it is that nuclear weapons will be used at some point.97 The situation in Northeast Asia helps illustrate how increasing the number of nuclear weapons states increases the probability that nuclear weapons will be used. Absent U.S. security guarantees, there is a real possibility that Japan, Taiwan, and South Korea would build nuclear arsenals of their own given their concerns about China and North Korea.98 There are currently two nuclear dyads in the region: the United States and China, and the United States and North Korea. If Japan, Taiwan, and South Korea all acquired nuclear weapons, there would be at least five additional dyads: China and Taiwan, China and Japan, China and South Korea, North Korea and South Korea, and North Korea and Japan. Given lingering tensions from its pre-1945 occupation of the Korean Peninsula, a South Korea-Japanese nuclear dyad is entirely plausible as well.99 Each new dyad adds a contest in risk-taking, which increases the chances that nuclear weapons will be used in the region.100 Though America’s geographic isolation insulates it from many the threats of an increasingly competitive and unstable world, it does not provide absolute immunity. As noted above, Christopher Layne rightly highlights the major wars in Europe in which the United States did not become involved. However, the question should not be about frequency of American involvement in major power wars in Eurasia. Instead, it should be about the cost when the United States does become involved in such a conflict. The purpose of insurance is to protect against low frequency, high-cost events. There was a relatively low probability that the Soviet Union would have invaded Western Europe during the Cold War, but the United States invested in deterring an invasion because the costs of an actual war would have been higher.101 While the United States avoided involvement in a number of European wars, the major conflicts the United States did become involved in were high-cost events. At the height of World War II, the United States spent 37 percent of its gross domestic product on its military.102 More than 8 percent of the U.S. population was in uniform at the war’s peak.103 The size of the American state expanded massively during this time.104 The United States did not need a formal military alliance with any of the belligerents prior to either of the world wars to become involved in the conflicts. America’s involvement in World War II suggests that one way the United States might become involved in another major war is if some former U.S. allies fail to build their military capabilities in the face of aggressive powers. Neoclassical realist scholars refer to this problem as “underbalancing.”105 According to this theory, states may fail to internally balance against a threat due to domestic political factors.106 If states fail to check an aggressive power, it could pave the way for the type of hegemonic threat realists believe would require American military action. If such a threat materialized, and if frontline states failed to contain it, the offshore balancing logic underpinning retrenchment recommends the United States regenerate its military capabilities to defeat it. Mearsheimer argues that these periodic military buildups are a feature of offshore balancing strategies. He writes: Offshore balancers like the United Kingdom and the United States tend to maintain relatively small military forces when they are not needed to contain a potential hegemon in a strategically important area… [W]hen it is necessary for an offshore balancer to check a potential hegemon, it is likely to sharply expand the size and strength of its fighting forces, as the United States did in 1917, when it entered World War I, and in 1940, the year before it entered World War II.107 Retrenchment assumes that this process would be somewhat mechanical. The United States, aware of a new threat and the inadequacy of frontline states to counter it, would convert its latent material strength into military power to confront, and if necessary, militarily defeat the threatening state.108 However, the process is unlikely to be as automatic or frictionless as realists suggest. Drawing on America’s economic resources to tap its latent military power would not provide the same advantage it did before World War II for two reasons. First, changes in military technology would make it difficult for the U.S. military to return to regions where it previously positioned forces. While modern technology enables the United States to project military power around the globe, it also makes it easier for potential adversaries to increase the cost of doing so. A number of states hostile to American interests have already procured anti-access and area denial (A2/AD) capabilities as a cost-effective means to prevent the U.S. military from operating near their respective territories.109 Second, tapping American economic power to mobilize for war would not be the same as it was before World War II. The economic conditions that obtained before the world wars are no longer with us. There is no great surplus of labor and idle manufacturing capacity as the Great Depression had provided the United States when it converted to a war economy prior to World War II.110 Converting to a war economy today would therefore require far-reaching political and social disruptions. In light of those disruptions, any effort to mobilize the American public for war would require a unifying mechanism. Realists assume nationalism is that mechanism. Ordinary Americans are unlikely to get worked up over the abstract threat of a distant regional hegemon in Eurasia. Confronted with a new military threat in Eurasia, American leaders are likely to rouse what historian Walter Russell Mead refers to as the populist “Jacksonian” tendency in American foreign policy. This tendency, Mead argues, leads to American wars that are particularly violent and destructive.11