The Department of Homeland Security has issued a National Terrorism Advisory System Bulletin in advance of the holidays. The United States remains in a heightened threat environment. Lone offenders and small groups motivated by a range of ideological beliefs and/or personal grievances continue to pose a persistent and lethal threat to the Homeland. Domestic actors and foreign terrorist organizations continue to maintain a visible presence online in attempts to motivate supporters to conduct attacks in the Homeland. Threat actors have recently mobilized to violence, citing factors such as reactions to current events and adherence to violent extremist ideologies. In the...