The roles played by the Egyptian, Tunisian, Libyan, and Yemeni armed forces during the Arab Spring are the latest chapter in a long story of political transitions in which the armed forces have played a positive role, or at least a passive role, in bringing unpopular dictatorships to an end. Citing the recent peaceful collapses of dictatorships as well as numerous other historical examples, this article examines the causes of transitions from military-supported dictatorships to more democratic governments, and proposes ways in which developed democracies can use their military-military relations to encourage democratic development.