How does the way states finance wars affect public support for conflict? Most existing research has focused on costs as casualties rather than financial burdens, and arguments that do speak to the cost in treasure either minimize potential differences between the two main forms of war finance—debt and taxes—or imply that war taxes do not dent support for war among a populace rallying around the fiscal flag. Using original experiments conducted in the United States and the United Kingdom, we evaluate the relationship between war finance and support for war. We find that how states finance wars has an important effect on support for war and that the gap in support resulting from different modes of war finance holds across the main democracies engaging in conflict, regardless of the type of war or individuals’ party identification. The findings have important implications for theories of democratic accountability in wartime and the conduct of conflict, since borrowing shields the public from the direct costs of war and in turn reduces opposition to it, giving leaders greater latitude in how they carry out war.