Brown Bag Seminar: Military Assistance and Conflict Duration: A theory of endogenous deterrence and resistance

This paper develops a tractable two-period dynamic game to isolate the strategic interaction between external military assistance and deterrence. We demonstrate that the equilibrium space is governed by the ordering of two endogenous variables: the defender’s resistance threshold, the minimum aid required to sustain defence over surrender, and the attacker’s deterrence threshold, the maximum intervention the aggressor is willing to confront before the costs of fighting outweigh the gains from aggression. Each threshold follows from a different participation constraint. Their ordering determines whether aid can create an

intermediate region in which the defender resists without deterring the attacker. Within that region, settlement feasibility determines whether the outcome is a negotiated settlement or a conflict trap. The finite-horizon extension provides a conditional characterisation of duration along histories for which the trap persists. Insufficient aid leads to rapid surrender, whereas sufficiently large transfers restore deterrence. Intermediate transfers combined with a level of costs which is lower than the reputational non-transferable gains, however, sustain resistance without deterring the attacker, giving rise to a conflict trap that lengthens the war. The emergence of this intermediate region is driven by the third party’s commitment problem, while its transformation into actual fighting depends on the attacker’s non-transferable battlefield prestige rent.