Scott Mainwaring is the Eugene and Helen Conley Professor of Political Science at the University of Notre Dame. His research interests include democratic institutions, democratization, and political parties and party systems. Among his previous books are Rethinking Party Systems in the Third Wave of Democratization: The Case of Brazil (1999), The Third Wave of Democratization in Latin America: Advances and Setbacks (co-edited, Cambridge University Press, 2005), The Crisis of Democratic Representation in the Andes (co-edited, 2006) and Democratic Governance in Latin America (co-edited, 2010). Mainwaring is a member of the American Academy of Arts and Sciences. In 2007, he was listed as one of the 400 most cited political scientists teaching in the United States. Aníbal Pérez-Liñán is an Associate Professor of Political Science and a member of the Center for Latin American Studies at the University of Pittsburgh. His research focuses on democratization, political institutions, and the rule of law in new democracies. He is the author of Presidential Impeachment and the New Political Instability in Latin America (Cambridge University Press, 2007) and has published articles in the Journal of Politics, World Politics, Comparative Political Studies, Comparative Politics, and Electoral Studies, among other journals. His research has been funded by the National Science Foundation, the United States Agency for International Development and the Inter-American Development Bank.