A Justice Department memorandum apparently prepared for Congress lays out for the first time the criteria that the national security establishment uses to decide whether to kill an American who is a senior al Qaeda leader or the the leader of one of its operational arms. Honors go to NBC's Mike Isikoff for the score. The memo has no classification markings on it, which tells me that it is a distillation from a larger, probably classified document prepared by the Office of Legal Counsel at the Department of Justice. Generally, the executive branch keeps secrets in one of two of ways. They classify something formally, or they claim that something not classified is tantamount to internal work product or private legal advice intended for the president and his advisers only.

This allows the administration to keep its internal legal memos away from other branches of government, which it claims the right to do. The Bush Administration revealed operational details of secret programs to Congress but refused to provide the legal reasoning. The Obama administration has, at least in the past two years, begun to brief members of Congress proactively on both sets of details. This is one reason why Congress, for the most part, isn't complaining about "secret laws." (There are some exceptions.)

Anyway, here is what the lawyers to the president's lawyer say about the legality of killing Americans who are constituted as al Qaeda or al Qaeda-linked threats. (The memo makes it clear that its language does not apply to other instances where American citizens might be killed by their government.)

1. "An informed, high-level official" must determine that the person represents "an imminent threat" of "violent attack against the United States."

2. Capturing the dude is "infeasible," and the government will continue to assess whether capturing him is feasible.

3. The killing, or "lethal operation," must be conducted according to the laws of war.

Sounds kind of broad. What about due process? The memo says that if the person presents an imminent threat to the homeland, then his due-process rights must be weighed against the obligation of the executive to protect the homeland. It asserts that the procedures it lays out do constitute a form of due process, (although, significantly, not judicial due process — all of this takes place within the executive branch).

It notes that the Supreme Court has as recently as 2006 acknowledged that the U.S. can use force against U.S. citizens engaged in armed combat against the U.S. And it doesn't matter if the person is planning to attack the U.S. from somewhere other than the place where an official war has been declared, so long as the country is determined to be a gathering place for al Qaeda and associated forces. Consent of the home nation? First, the administration will try to obtain it. If the home nation won't deal with the direct threat to U.S. interests, it reserves the right to act alone. Ok, but how does the executive branch determine whether a threat is imminent? Turns out it "does not require clear evidence" because the nature of terrorism and the asymmetries of information make it difficult to ever acquire such evidence. A "broader concept of imminence" is required.

So here's what that means: Even if the person is not actively planning terrorist attacks against the U.S., because of the nature of terrorist attacks in general, merely his membership in an organization that is planning those attacks meets the requisite definition of imminence.

So, basically, imminence does not mean imminent. And membership in al Qaeda is seen as tantamount to being in a car when someone decides to shoot someone on the street, even if the other occupant had no knowledge beforehand that the drive-by shooter would act. Accessory to murder, drone edition.