Right wing groups have the highest violence percentage then any other group.

Multiple authoritative sources analyzing political violence in the United States show that right-wing extremist groups account for the largest proportion of violent acts and fatalities compared to left-wing and Islamist extremists. For example, research from the University of Maryland's START program finds no significant difference between right-wing and Islamist violence levels but notes left-wing violence tends to be less severe.start.umd.edustart.umd.eduA Comparison of Political Violence by Left-wing, Right-wing and Islamist...

The Cato Institute reports that over half of politically motivated murders in recent years were committed by right-wing terrorists.time.comtime.comTrump Blames the Left for Violence. More Comes from Right Event-level data from ACLED confirms right-wing groups drove the majority of organized violent incidents from 2020 to 2023.profolus.comprofolus.comRight-Wing Extremists Drive Majority of U.S. Political Violence

Additionally, CSIS highlights white supremacist and right-wing extremist threats as the most significant terrorism concerns in the U.S.csis.orgcsis.orgThe Escalating Terrorism Problem in the United States While some sources note political violence overall remains rare, the preponderance of violent acts and fatalities are linked to right-wing actors.cato.orgcato.orgPolitically Motivated Violence Is Rare in the United States

There is less evidence supporting claims that left-wing groups have a higher violence percentage. However, nuances exist regarding definitions of violence, time frames, and types of incidents included. Overall, the consensus across multiple independent studies supports the claim that right-wing groups have the highest share of political violence in recent U.S. History.