Even if there is no intelligence indicating they are engaged in an active plot to attack the U.S. a citizen can be killed. Obama's dramatically increased use of drone strikes against al-Qaida suspects, including those aimed at American citizens, such as the September 2011 strike in Yemen that killed alleged al-Qaida operatives Anwar al-Awlaki and Samir Khan. Both were U.S. citizens who had never been indicted by the U.S. government nor charged with any crimes.
“This is a chilling document,” said Jameel Jaffer, deputy legal director of the ACLU, which has sued unsuccessfully in court to obtain administration memos about the targeted killing of Americans. “Basically, it argues that the government has the right to carry out the extrajudicial killing of an American citizen. … It recognizes some limits on the authority it sets out, but the limits are elastic and vaguely defined, and it’s easy to see how they could be manipulated.”