An unmanned drone armed with Hellfire missiles is shown over southern Afghanistan. A Hellfire missile fired from a drone was used in 2011 to kill an American in Yemen who the Obama administration says was an al-Qaida leader. Another American died in that attack, and a 16-year-old American was killed in a separate drone strike.
Lt. Col. Leslie Pratt/AP
October 2011: Men stand on the rubble of a building destroyed by a U.S. drone strike in southeastern Yemen. Among those killed was U.S. citizen Abdulrahman al-Awlaki, the son of U.S.-born cleric Anwar al-Awlaki — who himself was killed by a drone strike the month before.
Khaled Abdullah /Reuters /Landov
President Obama and John Brennan, his top counterterrorism adviser, in the Oval Office on Jan. 4, 2010. Brennan is a key voice about who gets put on the "kill list."
Pete Souza/White House