The authors of Why Civil Resistance Works present empirical evidence that, contrary to conventional wisdom, nonviolent resistance campaigns succeed at overthrowing regimes twice as often as violent campaigns, even in cases of a highly repressive state. Erica Chenoweth, an assistant professor of government at Wesleyan University, and Maria Stephan, a strategic planner with the U.S. Department of State, raise an original question and then employ quantitative and qualitative methods to reach their surprising findings. Unlike previous studies that focus solely on either violent or nonviolent campaigns, this book asks which type of campaigns are more successful at overthrowing regimes, ousting occupations, or facilitating secessions. The authors analyze 326 violent and nonviolent campaigns between 1900 and 2006, and they offer more in-depth study of the Iranian Revolution (1977–1979), the First Palestinian Intifada (1987–1992), the Philippine People's Power Movement (1983–1986), and the Burmese Uprising (1988–1990)—providing a range of scenarios where violent and nonviolent campaigns succeeded, partially succeeded, or failed. The authors define a successful campaign as one that discernibly results in the achievement of its own stated goals of regime change, anti-occupation, or secession within a year of peak activities.

There is no moral, bleeding-heart talking point here. Exacting debilitating costs on a state's sources of power rather than mere sentimental motivation underlie the nonviolent strategy. Such campaigns have two key advantages over violent resistance: (1) higher levels of participation and (2) leverage against the state. Moral, physical, informational, and commitment barriers to participation are much lower for nonviolent campaigns. An office worker need not take up arms and take cover behind rugged terrain to support a cause that she finds legitimate; such nonviolent tactics as protests, boycotts, civil disobedience, and strikes are far less dangerous activities. Nonviolence can also be an effective activity when civic disruption raises the costs of maintaining the status quo. As the state fails to provide basic services, more citizens may question the state's legitimacy and efficacy. When a population can leverage strategic gains against the state, the campaign benefits from higher resilience and a more diverse array of tactics. For example, even if the state cracks down on protests in the streets, a boycott of goods or a public transit strike may lead to concessions from leaders. Further, as participation rises, loyalty shifts among members within the establishment and security forces are more likely to swing as they become more affected by friends and family involvement.

Although the findings are impressive, they should not be overstated. Chenoweth and Stephan do not claim that nonviolence is always successful or that violence is never successful. Nonviolence is only slightly more effective than violence when campaign objectives focus on territorial gain or anti-occupation. In cases in which secession is the objective, both nonviolence and violence almost always fail. The authors offer explanations that are balanced and plausible, even if not ironclad and universal. For example, one in four nonviolent campaigns fails because they cannot win broad-based participation, leverage concessions, and erode bases of state power. Yet the main takeaway from the book should not be ignored. The counterintuitive findings are bound to raise questions and encourage further study among security scholars and policy-makers.