DesWhy do some wars persist long after the balance of power has become clear to both sides? This paper argues that political scientists have overlooked a critical dynamic feature of war: momentum. The prospect that battlefield momentum may shift even when the balance of power is clear creates obstacles to a negotiated settlement, especially in wars where total collapse is unlikely. Although military strategists have long emphasized momentum in operational design, existing theories of war termination have not systematically analyzed its political consequences. I conceptualize momentum as a dynamic feature of conflict: a temporary advantage that yields continued gains but remains subject to sudden reversal. I formalize the momentum shift as a Markov process embedded in a bargaining-while-fighting model, where leaders hold beliefs about its magnitude and durability. Equilibrium analysis shows that when momentum appears durable, the advantaged side inflates its demands beyond what the balance of power would predict; when momentum appears fragile, it moderates them; when momentum shifts sharply, both sides reassess their positions and delays settlement. I provide multi-level empirical evidence linking battlefield dynamics to political demands and war duration. Drawing on Chinese archival evidence from the Korean War, I show how Mao assessed battlefield momentum to calibrate China's negotiating position. I then analyze data on 98 interstate wars (1823–1999), covering more than 35,000 war-days. I find that sharp momentum shifts delay settlement, whereas states are more likely to enter negotiations, reach settlements, and cease fighting when one side sustains momentum. cription tjjext goes here

Using Chinese archival records with Mao’s telegram with both military general and diplomats, I construct the Korean War decision making circle and show that advice to compromise is only heard when it comes from a leader's most trusted generals or direct order from Stalin. For everyone else in the decision-making circle, suggesting compromise carries severe personal and political risks—creating a structural obstacle to war termination.

What drives belligerents’ decisions of when to stop fighting and when to negotiate during interstate war? This paper shows an empirical puzzle of changing patterns in wartime negotiations after World War II: states substitute post-ceasefire negotiations with pre-ceasefire negotiations. I examine the duration of negotiations before and after ceasefires with a dataset of 91 interstate wars from 1823 to 2001, featuring 35,521 conflict days. I find that, first, fewer negotiations occured after ceasefire post-World War II, compared to pre-World War II period. Second, wartime negotiations lasted longer. Using a multi-state hazard model with time-varying covariates, I show that fighting is less likely to end after negotiation begins after 1945. Why do states negotiate more during the war but avoid peaceful negotiation after ceasefire? I argue that increased domestic and international pressure for peace after World War II increased the cost of restarting war, making negotiation after ceasefire inefficient for belligerents. Thus, states have an incentive to prolong negotiations before ceasefire to gain concrete advantage in the resulting settlement. I demonstrate this strategic calculation using a case study of the 1988 Iraq-Iran ceasefire negotiation, where two sides bargained over what needed to be negotiated before implementing a UN-sponsored ceasefire.