Use Their Force: How Alliances Shape the Distribution of Military Capabilities

• In Event: Fighting with Friends: Alliances and Military Effectiveness

Abstract

Why do some capable states have imbalanced, specialized militaries while other maintain balanced, diversified force structures? Scholars and practitioners have long maintained that a full spectrum combined-arms military is the best defense against an unpredictable enemy. But that fails to explain why the US omitted minesweepers from its planned 600 ship navy in the 1980’s or why Western European states possessed no aerial refueling capacity until well after the end of the Cold War. Are specialized militaries that forgo the development of vital defense capabilities simply making mistakes? I argue that while there are strategic advantages of a diversified military portfolio, there are conditions under which states can reap the gains of economic efficiency that come with specialization without sacrificing the security benefits of a full spectrum force. States can specialize their defense capabilities when they engage in security cooperation with allied states. When a collection of states facing a similar threat environment are able to institutionalize their defense relationship in way that builds trust, minimizes the risk of defection, and ensures effective coordination, they can each individually specialize in different military capabilities that, when brought together, still comprise a full spectrum combined-arms military force. I substantiate these arguments with evi- dence from a new dataset on state military capabilities since 1970 and find states have more specialized militaries when 1) they participate in military alliances and 2) those alliances have shared interests and are institutionally hierarchical.

Author

• J Andres Gannon, University of California, San Diego