While a variety of violent extremist movements have attempted to assault American critical infrastructure throughout modern history, the Department of Homeland Security and other national security authorities have recently sounded the alarm that U.S.-based violent extremists have developed “credible, specific plans” to attack critical infrastructure.

To understand the current dimensions of this threat, this paper reviews 94 cases of individuals charged in the U.S. federal court system from 2016 to 2022 with planning to conduct violent extremist attacks, 35 of whom attempted to attack critical infrastructure systems.

This report offers insights for practitioners to better understand the scope of the threat against U.S. critical infrastructure and address target hardening needs with private industry partners.