Ehrhardt researches citizen electoral behavior in liberal democracies, particularly in Europe. Her dissertation examines the conditions which drive individuals to vote for ethno-nationalist terrorist-affiliated political parties within these countries with an emphasis on the Northern Ireland case. In particular, she is interested in how local demographics and the proximate level and nature of violence shape electoral preferences independent of changes at the national level. Her other research interests include ethnic conflict (particularly the Basque case), nationalism and its relationship to further EU integration, and quantitative and formal methods.