The literature on war deals with finances, causes, or consequences. But, how do war-related expenditures affect economically-relevant outcomes at a war’s conclusion (e.g., prevailing side, duration, and casualties)? I present a model of attrition and characterize the effects of GDP at a military conclusion (one side cannot fight anymore) and a political conclusion (one side quits). The estimated model fits the data for the battle of Iwo Jima well. Analyzing data for the current Russo-Ukrainian war through the lenses of the model suggests that additional support to Ukraine could yield a shorter, cheaper war with less destruction on both sides.