What explains the variation in how states pay for war? Leaders must choose between four primary means of war finance: taxation, domestic debt, external extraction, and printing. Each alternative has different political and economic costs and benefits. Borrowing compounds the cost of war through high interest rates; printing can result in disastrous inflation; taxation combats high inflation and minimizes cost yet can be politically damaging; while garnering money from abroad invites outside influence and fosters dependency. Conventional wisdom suggests that regime type dictates war finance strategy. However, based on statistical analysis of a novel data set and in-depth case studies, I demonstrate that regime type plays at best only a small...