But what does "an associated force" mean? It seems like the guy who sells the terrorists bomb supplies would probably qualify, but what about the unknowing neighbor or the hired hand? Can we just kill them too in good conscience? Quite unfortunately, the government isn't exactly sure. The memo suggests that anyone who "present[s] an 'imminent' threat of violent attack against the United States" qualifies for assassination "a lawful killing in self defense," but that "does not require the United States to have clear evidence that a specific attack on U.S. persons and interests will take place in the immediate future." In other words, an "informed, high-level" official can order the killing of any American citizen that was "recently" involved in threatening "activities." As Isikoff points out, the memo fails to define both of those terms.

"This is a chilling document," said Jameel Jaffer, deputy legal director of the American Civil Liberties Union. "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." We've already seen some of this vague authority in action. A couple of years ago, The New York Times provided some insight into how subjective the process of deciding when to kill and when not to kill American citizens based on the vague outlines of a top secret memo that justified the killing of al-Awlaki. That document as well as this latest leak from the Justice Department (which is also mostly a vague outline) essentially combine to say that a lethal attack, likely by a drone, is the method of choice whenever a capture mission would put other American lives on the line. Again, the documents are very vague about where to draw the line.

Inevitably, this latest revelation into how the Obama administration runs the War on Terror behind closed doors leads to more questions than answers. How, for instance, does this justify the killing of al-Awlaki's 16-year-old, American-born son? Surely he was "associated" with his father, but not an "associated force." And how does the administration decide when to kill non-U.S. citizens? Previous reporting on the issue says that the government considers any military-aged male to be an insurgent, so it seems like pretty much anybody in the general region of Afghanistan or Pakistan could expect to find themselves in America's crosshairs. But again, we don't know because the Obama administration is keeping it completely secret, despite years worth of calls to disclose its decision-making process.

This could be the beginning of an enlightening time for those who demand answers about the government's shady drone program. On Thursday, John Brennan has his confirmation hearing where the Senate will decide whether or not he's fit to run the Central Intelligence Agency. Since he's more or less the architect of America's drone war, we're sure the Senators will have a question or two about this memo and, we hope, some other documents that we haven't seen yet — such as the full 50-page version of the memo, of which this latest leak merely contains a white-paper sketch. Because at least 11 Senators from both parties are already asking for more.

Update, Tuesday morning: What the White House Still Hasn't Said About Drones

This article is from the archive of our partner The Wire.

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