AER: Insights

Long Wars

2026-05-27

We study whether the Coase conjecture holds for bargaining during war. Two players, A and B, contest a divisible resource until one side collapses or agreement is reached. If player B is militarily strong, then he insists on getting a large share. However, player A only concedes this large share if player B credibly signals his strength by fighting a sufficiently long war. Thus, the Coase conjecture fails, and asymmetric information about military strength explains why long wars may be inevitable. Using a mechanism design approach, we derive a lower bound on the expected duration of war. (JEL C78, D74, D82, F51)

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DOI https://doi.org/10.1257/aeri.20240624