Preventing the recurrence of civil war has become a critical problem for both scholarship and policy. Conventional wisdom urges the creation of capable, legitimate, and inclusive postwar states to reduce the risk of relapse into civil war, and international peacebuilders have often encouraged the formation of a new national army that would include members of the war's opposing sides. However, both the theoretical logics and the empirical record identifying military integration as a significant contributor to durable post–civil war peace are weak. An analysis of eleven cases finds little evidence that military integration played a substantial causal role in preventing the return to civil war. Military integration does not usually send a costly signal of the parties’ commitment to peace, provide communal security, employ many possible spoilers, or act as a powerful symbol of a unified nation. It is therefore both unwise and unethical for the international community to press military integration on reluctant local forces.