Political Economy of Military Alliances

A prominent topic in the political economy of security is the political economy of alliances, which focuses largely on two core topics: the "arms-versus-allies" tradeoff, and the linkages between economic cooperation and security cooperation. Overall, my research on this topic has made two contributions to our understanding of how military alliance pacts are connected to economic issues.

First, my doctoral dissertation shed new empirical insights into how economic cooperation enhances security cooperation. I did this by showing that economic cooperation can be used to enhance the credibility of an alliance commitment and that offers of economic cooperation can be used to secure military cooperation in the first place. This also allowed me to bring new insights into the more general research into how ``issue linkages'' enable states to achieve "cooperation under anarchy." Issue linkages are when states decide to include two or more unrelated issues in a single agreement. The logic is that including multiple issues in a single agreement -- thereby providing "something for everyone'' -- will make all the parties willing to sign on and adhere to a cooperative agreement. Though this concept has a long literature, it lacked empirical evidence.

The first half of the dissertation sought to determine if linking issues raised the probability of agreement substantially (say by 25 percentage points), marginally (say by 1 percentage point), or not at all. I used the inclusion of trade cooperation provisions in miliary alliance treaties as a means of gaining empirical leverage on this question, as trade cooperation and military cooperation are two issues that are clearly separable (meaning states can and have negotiated agreements on just trade or on just alliances). I collected new data on failed alliance treaty negotiations and identifying whether those negotiations witnessed trade cooperation offers. After combining my data on failed negotiations with existing data on when states have formed alliance treaties, I then estimated that offers of issue linkage raised the probability of agreement by over 30 percentage points.

The second half of the dissertation evaluates whether linking issues enables states to remain committed to an agreement, which is one of the fundamental problems in the international system. I use the alliance relations of buffer states (states located between two recently or currently warring rivals) to test the claim that issue linkage enhances compliance with treaty obligations. The alliance relations of buffer states create a `hard case' for treaty compliance because buffer states are especially prone to invasion and occupation, thereby making other states reluctant to remain committed to an alliance agreement with the buffer state. Hence, if linkage provisions can enhance the credibility of alliance commitments for buffer states, then linkage provisions should improve treaty compliance in nearly any context. I find that buffer states in alliances with trade provisions experience fewer opportunistic violations of the alliance terms, avoid occupation and invasion at a higher rate, and experience fewer third party attacks than buffer states in other alliance arrangements.

The dissertation was published as a series of papers, including in International Organization and the Journal of Conflict Resolution, and received the Walter Isard Best Dissertation Prize from the Peace Science Society. The policy implications of this research are highlighted here.

Second, in a series of co-authored papers, I helped unpack how states choose between security via their own arms, security via the assistance of an ally, or security using both means. Realist scholars have long identified internal balancing (via arms) and external balancing (via allies) as the two core ways that states can oppose a threat. Additionally, a rich literature seeks to identify the conditions under which arms and allies are substitutes, complements, or a bit of both. Given that research on the ``arms versus allies'' tradeoff directly links the political economy of military power with the political economy of acquiring allies, exploring such questions was a natural extension of my existing research.

My own contributions to this literature has appeared in The British Journal of Political Science and The Journal of Conflict Resolution. In the former piece, we argue that since democratic states are perceived as more reliable allies, states are more likely to reduce military expenditures after forming an alliance with a democracy. In the latter piece, we argue that adopting a conscription-based military recruitment system signals a willingness to incur domestic political costs for the sake of security, thereby easing the ability of a state to form an alliance. Hence, this form of internal arms is a complement to allies.