Keeping Your Friends Close, but Acquaintances Closer: Why Weakly Allied States Make Committed Coalition Partners

Abstract

Why do states join wartime coalitions despite the absence of a salient threat or strong ties to the coalition leader? We argue states make unexpectedly high contributions to coalition warfare as a costly signal of their desire for a stronger relationship with the coalition leader. Conventional theories insufficiently explain why states without immediate security interests or strong ties to the lead state over-contribute relative to their capacity. Using newly compiled data on troop contributions to the war in Afghanistan (2001–2014), we find states are most likely to contribute a higher share of their armed forces when their relationship with the US has unrealized alliance potential. States with under-performing alignments leave substantial room for subsequent gains to be had from signaling their commitment to the leading coalition actor. Our finding helps explain why states risk the costs of war—casualties and domestic accountability—by participating in coalition warfare.

Elite Cues and Public Attitudes Towards Military Alliances

“…The financial costs reflect a rough association between an alliance commitment and U.S. military spending from Alley and Fuhrmann (2021). Recent military cooperation can bolster a partner’s reputation (Crescenzi et al, 2012; Gannon and Kent, 2020). I also randomize the region of the hypothetical alliance partner to mitigate confounding on other dimensions like cultural similarity.…”