Many of the post-Communist states of Eastern Europe have chosen to enact a vetting procedure known as lustration to ban former secret police agents and their informants from holding public office. This practice is part of a global trend toward increasing accountability for human rights violations. In this dissertation, lustration policies are examined within this context. First, an original dataset covering all post-Communist states in Europe and the former Soviet Union for the period 1989 to 2012 is used to analyze competing explanations for the proposal and enactment of lustration laws. Discrete-time logistic regression shows that democratization and control of the government by Left parties are strong predictors of lustration. Second, the extended case method is applied to the case of lustration to resolve a theoretical paradox. World polity neoinstitutionalist theory would predict that lustration should not be occurring. Drawing on insights and concepts from other areas within sociology, the paradox is resolved and a revised theoretical framework is proposed. Third, the cases of Croatia, Serbia, and Macedonia are examined using the strategic narrative method of historical sociology. The cases were chosen because of their varied outcomes with lustration--no law in Croatia, a law without enforcement in Serbia, and a law with enforcement in Macedonia. Analyses of these cases show both the power and the limits of path-dependent explanations in historical sociology. Finally, the implications of lustration for democratization and transitional justice are discussed.