Although pacifism and nonviolence bear a close relationship to one another historically, pacifism is the ideological assertion that war and violence should be rejected in political and personal life, whereas nonviolence refers to a distinct set of political practices. Unlike other modern ideologies such as liberalism and socialism, pacifism has never gained widespread acceptance among a significant portion of humanity and seems to remain a minority position among most of the peoples of the world. Even among those who use nonviolent techniques, the conventional wisdom that physical violence is necessary under certain circumstances often prevails. However, a growing body of empirical evidence shows that the methods of nonviolence are more likely to succeed than methods of violence across a wide variety of circumstances and that more people are using nonviolence around the world. At the same time, both the effectiveness of military and material superiority in achieving political ends and the incidence of warfare and violence appear to be waning. In a remarkable example of convergence between empirical social science and political theory, explanations for the effectiveness of nonviolence relative to violence point to a people-centered understanding of power. This research can provide a basis for a reinvigorated and pragmatic brand of pacifism that refocuses the attention of political scientists on the organization, actions, and loyalties of people as opposed to technologies of domination and destruction.