The Obama administration justified using drones to kill Americans suspected of terrorism overseas by citing the war against al-Qaida and by saying a surprise attack against an American in a foreign land would not violate the laws of war, according to a previously secret government memorandum.
The memo released yesterday provided legal justification for the September 2011 killing in Yemen of Anwar Al-Awlaki, an al-Qaida leader and one-time cleric at a northern Virginia mosque who had been born in the United States, and another US citizen, Samir Khan, who edited al-Qaida's Internet magazine.
An October 2011 strike also killed Abdulrahman al-Awlaki, al-Awlaki's teenage son and also a US citizen.
The memo, written by a Justice Department official, said the killing of al-Awlaki was justified under a law passed by Congress soon after the September 11, 2001, terror attacks.
The law empowered the president to use force against organisations that planned, authorised and committed the attacks.
Al-Awlaki had been involved in an abortive attack against the United States and was planning other attacks from his base in Yemen, the memo said.
It said the authority to use lethal force abroad may apply in appropriate circumstances to a US citizen who is part of the forces of an enemy organisation.
The memo stated the Defence Department operation was being carried out against someone who was within the core of individuals against whom Congress had authorised the use of "necessary and appropriate" force.
It said the killing was justified as long as it was carried out in accord with applicable laws of war.
The 2nd US Circuit Court of Appeals in Manhattan released the memo, portions of which were blacked out, after the American Civil Liberties Union and The New York Times filed a lawsuit seeking any documents in which Justice Department lawyers had discussed the highly classified "targeted-killing" program.
The appeals court ordered the memo disclosed after noting that President Barack Obama and other senior government officials had commented publicly on the subject.
White House spokesman Josh Earnest, responding to criticism from groups that complained that it took a court order to get the memo released, said the administration worked through the legal system "to produce a redacted document that protected national security interests while at the same time trying to live up to our commitment to transparency."