Explore the vast range of titles available.

Many critical questions involving the causes and consequences of formal military alliances are related to differences between various alliances in terms of the scope of the formal obligations, the depth of the commitment between signatories, and the potential military capacity of the alliance. Studying the causes and consequences of such variation is difficult because while we possess many indicators of various features of an alliance agreement that are thought to be related to the broader theoretical concepts of interest, it is unclear how to use the multitude of observable measures to characterize these broader underlying concepts. We show how a Bayesian measurement model can be used to provide parsimonious estimates of the scope, depth, and potential military capacity of formal military alliances signed between 1816 and 2000. We use the resulting estimates to explore some core intuitions that were previously difficult to verify regarding the formation of the formal alliance agreement, and we check the validity of the measures against known cases in alliances as well as by exploring common expectations regarding historical alliances.

When are economic sanctions expected to succeed? Previous studies predict that sanctions will be more effective when the issue at stake is important, when the sender and target are allied, when the target's domestic institutions are more democratic, and when the target's economy is dependent on the sender's. This article subjects these explanations to an empirical test using a new fully structural estimation that employs a game theoretic model as a statistical model. The initiation and outcomes of sanctions are incorporated with the strategic behaviors of sender and target states into a unified model. The model improves upon extant models by allowing the initial choice of the sender states to be multiple, not binary. This non-binary option enables the sender states to opt for the optimal intensity level of sanctions. Findings suggest that issue salience is positively associated with the decision to impose sanctions, but not necessarily with their effectiveness. Further, allied targets tend to comply even when they can win a sanctions contest, while non-allied targets tend to resist even when they know that on average the sender is likely to continue sanctioning in the face of resistance. Since sanctions imposed from 1903 to 2002 take place disproportionately between non-allied dyads, and thus belong to the category of sanctions most likely to fail, we can begin to understand why sanctions have such a low success rate.

How can states signal their alliance commitments? Although scholars have developed sophisticated theoretical models of costly signaling in international relations, we know little about which specific policies leaders can implement to signal their commitments. This article addresses this question with respect to the extended deterrent effects of nuclear weapons. Can nuclear states deter attacks against their friends by simply announcing their defense commitments? Or must they deploy nuclear weapons on a protégé's territory before an alliance is seen as credible? Using a new dataset on foreign nuclear deployments from 1950 to 2000, our analysis reveals two main findings. First, formal alliances with nuclear states appear to carry significant deterrence benefits. Second, however, stationing nuclear weapons on a protégé's territory does not bolster these effects. The analysis yields new insights about the dynamics of \"hand-tying\" and \"sunk cost\" signals in international politics.

The academic study of defense cooperation focuses heavily on formal military alliances. Yet, governments rarely sign new alliances, and the global alliance structure has remained relatively static for decades. By contrast, governments are increasingly active in defense cooperation agreements (DCAs). These bilateral framework treaties institutionalize their signatories’ day-to-day defense relations, facilitating such wide-ranging activities as defense policy coordination, joint research and development, weapons production and arms trade, joint military exercises, training and exchange programs, peacekeeping, and information exchange. Nearly 2,000 DCAs have been signed since 1980. Preliminary evidence suggests that DCAs impact numerous security, military, and defense outcomes and that governments increasingly incorporate DCAs as core elements of their security strategies. This article introduces the new DCA Dataset (DCAD). I provide a brief historical background on DCAs and compare them to other commonly studied forms of defense cooperation. I then explain coding standards and describe the data set in detail. Finally, I illustrate applications of DCAD to militarized interstate disputes and arms trade.

Scholars think that friendly nations adopt secrecy to avoid domestic costs and facilitate cooperation. But this article uncovers a historical puzzle. Between 1870 and 1916, over 80 percent of alliance ties were partially or completely covert. Otherwise, hidden pacts are rare. Why was secrecy prevalent in this particular period and not others? This article presents a theory of “portfolio consistency.” Public agreements undermine the rank of hidden alliances. A partner willing to openly commit to another country but not to you signals the increased importance of this other relationship. States pressure their covert partners to avoid subsequent public pacts. This creates a network effect: the more secret partners a state has, the greater the incentives to maintain secrecy in later military agreements. Covert alliances have a cumulative effect. In seeking the flexibility of hidden partnerships, states can lock themselves into a rigid adherence to secrecy.

A number of proposals for reducing tensions with North Korea have discussed alterations to the program of joint military exercises (JMEs) that South Korea holds. North Korea has also repeatedly called for a reduction or secession of JMEs. Would limiting or halting JMEs be a useful concession for securing a reduction of tensions on the peninsula? We argue that JMEs do not deter North Korea but, instead, provoke provocative rhetoric and actions, demonstrating that North Korea views JMEs as a serious threat to its security. In this paper, we establish a relationship between JMEs and North Korea’s actions. In response to a JME, North Korea can issue warnings or threats as well as take costly signals such as conducting missile or nuclear tests. Using new data on JMEs and North Korean behavior, we find that North Korea systematically responds with aggression to South Korean JMEs. Moreover, we find that the intensity of North Korea’s responses to JMEs is driven by the severity of the threat particular exercises pose, indicating that North Korea responds to JMEs as serious security threats.

This paper addresses military innovation in Finland in the context of the country’s NATO integration. Finland shifted its security policy course rapidly and dramatically when it applied for NATO membership in May 2022, less than three months after the Russian full-scale invasion of Ukraine. The main argument of the paper is that various military innovations are taking place as Finland – after decades of neutrality and later non-alignment policy – seeks its role within the alliance. However, those innovations are mostly incremental in nature. Many earlier fundaments of Finland’s national defence, such as conscription and models of comprehensive security and comprehensive defence, will remain in place. If they are transformed, it will happen in an evolutionary way, by adjusting existing practices, not by launching revolutions.

Evidence suggests that leaders of democratic states experience high costs from violating past commitments. We argue that because democratic leaders foresee the costs of violation, they are careful to design agreements they expect to have a high probability of fulfilling. This may cause democratic leaders to prefer flexible or limited commitments. We evaluate our argument by analyzing the design of alliance treaties signed by countries of the world between 1815 and 2003. We find that alliances formed among democratic states are more likely to include obligations for future consultation rather than precommitting leaders to active conflict, and defense pacts formed among democratic states are more likely to specify limits to the conditions under which member states must join their partners in conflict. This research suggests that separating screening effects and constraining effects of international agreements is even more difficult than previously believed. States with the greatest likelihood of being constrained are more carefully screened.

We study the factors that influence citizen support for defense spending in fourteen democracies over the period 2004–2013. We pose two research questions. First, what factors influence citizen support for war and military force? We refer to this as the acceptability of war. Second, in addition to the acceptability of war, what other factors affect support for defense spending? Our principal finding is that citizen acceptance of war and support for defense spending are most influenced by basic beliefs and values. Gender also has a strong negative influence on attitudes toward war and thus indirecdy lowers support for defense spending among women. Attitudes toward war and defense spending are also sometimes influenced by short-term threats and by alliance considerations, but the effects are not as substantively meaningful. We conclude with a summary of the results and a discussion of the implications for theory and policy.

Creating institutions that effectively manage interstate conflict is a priority for policy-makers. In this article we demonstrate that military allies are well positioned to influence the crisis-bargaining behavior of both challengers and targets in ways that often lead to peace. Through a three-player game-theoretic model, we demonstrate that a target's alliances not only have an effect on the demand that the challenger makes, but also on the behavior of the target. When a target values an alliance highly, an ally's recommendation for settlement can encourage the target to concede to demands without further escalation. Our statistical analysis provides evidence in support of the theoretical finding. Allies can both deter challengers and restrain partners, and as a result, can encourage peaceful behavior not only from adversaries, but from member states as well. Our study thus sheds new light on the role of military alliances as potential conflict management devices.