Offshore Hegemony, Buck-Passing, and Regional Conflict: A Dynamic Optimization Model of Conflict

This paper develops a dynamic optimization model of great-power interaction to explain when an offshore hegemon intervenes directly in a regional war and when it rationally chooses buck-passing. The framework models a sole global hegemon, a revisionist regional power as a partial challenger, and a large but militarily constrained coalition as an imperfect balancer. The key contribution is a continuous-time optimal stopping model in which intervention is irreversible, costly due to distance, and subject to low-probability but catastrophic nuclear escalation. Battlefield conditions evolve stochastically, while regional military capabilities change slowly. The model delivers a threshold policy for intervention and a structural non-intervention equilibrium when escalation risk, geographic distance, and partial regional balancing raise the value of waiting above the payoff from intervention at all states. Applied to the Russia-Ukraine conflict, the model explains prolonged war with limited U.S. involvement despite overwhelming American military superiority. The analysis clarifies why Russia need not be a full regional hegemon to deter intervention and why European assistance, while insufficient to end the conflict, rationally sustains U.S. restraint.