Pape began studying the causes and viable solutions to political violence in the 1990s, focusing on the 1992-1995 Bosnian War and the 1999 War in Kosovo. His work on suicide terrorism (2003, 2005, 2010) explained that it is mainly a form of political violence, while his work on humanitarian intervention (2012) centered on appropriate international responses to political violence related to the Arab Spring in Libya and Syria. In 2017, Pape published an analysis of political violence in Iraq, Afghanistan, Pakistan. In January 2018, Pape testified before the House Subcommittee on National Security on the military defeat of ISIS.