She received her PhD in Political Science, with distinction, from Yale University. She has taught at the Institut d'tudes Politiques de Lille, served as political science program director at the National Science Foundation, and is a former president of the American Political Science Association's Conference Group on Italian Politics and Society. Mershon's articles have appeared in journals such as the American Political Science Review, the American Journal of Political Science, Comparative Politics, Comparative Political Studies, Electoral Studies and the Journal of Politics, among others. She is the author of The Costs of Coalition (2002) and the co-editor of Political Parties and Legislative Party Switching (2009). The recipient of two awards from the National Science Foundation, Mershon has also held two Fulbright grants and a Social Science Research Council Fellowship.