We study the factors that influence citizen support for defense spending in fourteen democracies over the period 2004–2013. We pose two research questions. First, what factors influence citizen support for war and military force? We refer to this as the acceptability of war. Second, in addition to the acceptability of war, what other factors affect support for defense spending? Our principal finding is that citizen acceptance of war and support for defense spending are most influenced by basic beliefs and values. Gender also has a strong negative influence on attitudes toward war and thus indirectly lowers support for defense spending among women. Attitudes toward war and defense spending are also sometimes influenced by short-term threats and by alliance considerations, but the effects are not as substantively meaningful. We conclude with a summary of the results and a discussion of the implications for theory and policy.