This study investigates why democracies tend to win the interstate wars they fight, as claimed by the theory of democratic victory. This study introduces the novel argument that the concept of quality of government can explain the success of democracies in war. Analyzing all interstate wars between 1816 and 2007 with a multivariate logit model, this study finds initial support for the hypothesis that a rigorous and impartial public administration is a better explanation for why democracies tend to win interstate wars than the democratic institutions themselves. No support is found for any of the other hypotheses that other aspects of quality of government, such as low corruption or the practice of meritocracy, can explain democracies’ relative success in war. This study thereby sheds new light on why democracies tend to be successful in interstate wars and indicates an interesting avenue for further research.