Année
2026
Abstract
We develop a global games model of a defense alliance to analyze how higher-order beliefs shape the decision to undertake military action against a common threat. In the model, two allies differ in their costs of intervention, and one ally exhibits a systematic perception bias that distorts its assessment of the strategic stakes. Under heterogeneous information, the game presents a threshold equilibrium, allowing us to characterize the determinants of each ally’s probability to engage its military forces in the defense of the common goal. We show that asymmetries in costs and perception biases generate spillovers that can undermine coordination within the alliance. These mechanisms shed light on current challenges facing NATO, including Russia’s threats on its Eastern flank and the prospect of a more isolationist United States.
VRANCEANU, R. et COLSON, A. (2026). Resilience of Defense Alliances: A Global Games Approach. WP 2602, ESSEC Business School.