In recent months, several high-profile incidents have raised awareness of the threat posed by individuals and small groups operating under the principles of leaderless resistance . These incidents have included lone wolf attacks against a doctor who performed abortions in Kansas, an armed forces recruitment center in Arkansas and the U.S. Holocaust Memorial Museum in Washington, D.C. Additionally, a grassroots jihadist cell was arrested for attempting to bomb Jewish targets in the Bronx and planning to shoot down a military aircraft at an Air National Guard base in Newburgh, N.Y. In addition to pointing out the threat posed by grassroots cells and lone wolf operatives, another common factor in all of these incidents is the threat of violence to houses of worship. The cell arrested in New York left what they thought to be active improvised explosive devices outside the Riverdale Temple and the Riverdale Jewish Community Center.