Al Awlaki assassination raises legal questions

to the government’s assassination list, if a U.S. citizen joins al Qaeda, "it doesn't really change anything from the standpoint of whether we can target them.”

"They are then part of the enemy,” the official concluded.

When it was first announced that al Awlaki had been placed on the U.S. assassination list, his father sued unsuccessfully to block the move. In December 2010, a federal judge dismissed the lawsuit writing that al Awlaki’s father had no standing to sue on his son’s behalf and that targeted killings were a “political question” for executive officials to answer, not judges.

However, the judge was careful to note that the case raised “stark, and perplexing, questions” like whether the president could “order the assassination of a U.S. citizen without first affording him any form of judicial process whatsoever, based on the mere assertion that he is a dangerous member of a terrorist organization.”

In a blog post, Greenwald pointed to a 1981 Executive Order signed by Ronald Reagan that prohibits assassination by any government official or representative of the U.S. government.

The text reads, “No person employed by or acting on behalf of the United States Government shall engage in, or conspire to engage in, assassination.”

In contrast, Charlie Dunlap, a visiting law Professor at Duke University, pointed to Ex Parte Quirin, a Supreme Court case from 1942 involving a Nazi saboteur that granted the U.S. government the authority to kill one of its citizens if they became an enemy to the state.

“The court explicitly found that ‘there are circumstances in which the executive's unilateral decision to kill a U.S. citizen overseas is constitutionally committed to the political branches and judicially unreviewable,’” Dunlap said.

"In short, if a U.S. citizen overseas presents an imminent threat, or is a participant in an organized armed group engaged in armed conflict against the U.S., as the administration seems to be alleging is the case with al Awlaki, the mere fact that he may also be accused of criminal offenses does not necessarily give him sanctuary from being lawfully attacked overseas as any other enemy belligerent might be.”

Al Awlaki’s death is not the first killing of an American citizen.

In 2002, Kamal Derwish, an American from outside of Buffalo, New York who had joined al Qaeda, was killed in a drone strike in Yemen. At the time, administration officials said they were not aware that Derwish was in the vehicle before it was struck by a missile and that he was not the intended target of the strike.

Regardless, administration officials expressed little concern that Derwish was in the vehicle because he was an al Qaeda operative and therefore an enemy.