Professor of Political Science at Villanova University. He has been working on the origins of European and post-communist party systems as well as qualitative methodology. He is the author of Institutions and Innovation: Voters, Parties, and Interest Groups in the Consolidation of Democracy – France and Germany 1870-1939 (Michigan 2001) and The Grammar of Time: Using Comparative Historical Analysis to Study the Past (Cambridge, forthcoming). He is interested in the conundrum of how to study a disorderly and continuously changing world in the most orderly fashion possible and with methodologies mindful of temporal dynamics. To disentangle this conundrum, he looked at how comparative historical analysis employs a nuanced temporal vocabulary, uses distinct notions of causality, and draws on a more heterodox understanding of methodology than standard variance-based analysis. His articles have dealt with path dependency, conceptions of time, historical exceptionalism, conceptualizations of historical change, proper use of historical evidence, and the nature of historical description. They have appeared in the American Political Science Review, World Politics, British Journal of Political Science, Comparative Politics, Central European History, and Perspectives on Politics.