Desposato joined the faculty in at University of California San Diego in Fall 2005 as an Associate Professor of Political Science. His general research interests include democratic institutions, campaigning, mass behavior, and political methodology. Specific projects have examined redistricting in the United States, electoral rules and federalism in Brazil, party-switching by politicians, and statistical methods for studying legislatures. Published research has appeared in The American Journal of Political Science, The Journal of Politics, Comparative Political Studies, and Political Analysis. His latest project, for which he has received a National Science Foundation award, examines the determinants and impacts of negative campaigning across different institutional settings.