After the Cold War ended, promoting the international spread of democracy seemed poised to replace containment as the guiding principle of U.S. foreign policy. Scholars, policymakers, and commentators embraced the idea that democratization could become America's next mission. In recent years, however, critics have argued that spreading democracy may be unwise or even harmful. This paper addresses this debate. It argues that the United States should promote democracy and refutes some of the most important arguments against U.S. efforts to spread democracy. After a brief discussion of definitions of democracy and liberalism, the paper summarizes the reasons why the spread of democracy— especially liberal democracy— benefits the citizens of new democracies, promotes international peace, and serves U.S. interests. Because the case for democratization is rarely made comprehensively, the paper explicates the arguments for why democracy promotes liberty, prevents famines, and fosters economic development.