Jonathan Keith "Jack" Idema (May 30, 1956 – January 21, 2012) was an American mercenary and former United States Army reserve non-commissioned officer, known for his vigilante activities during the War in Afghanistan. Formerly a member of the U.S. Army Special Forces, Idema never saw combat and left the military in 1984 to form several companies centered around counterterrorism and internal security. Idema made numerous unverified claims about his military service and supposed terrorist threats, and experienced several lawsuits over various feuds.