I've finally been driven bonkers by the quality of the discussion on the left about drone use against US citizens within the United States. OF COURSE it's constitutionally permissible for executive officials to take actions against a US citizen on US soil that either (a) predictably will lead to the citizen's death or (b) are intended to kill the citizen. (Drones are completely irrelevant to the constitutional question. Snipers using rifles raise the same question. And, in this post I'm talking only about the Constitution; there are statutory limitations on who can do the killing -- for example, not the CIA -- but I'm not going to deal with them.) The only interesting questions, and they aren't all that interesting, deal with when it's constitutionally permissible to do so -- and, secondarily, with what processes do the officials have to go through before they take the action.
Start with a simple example where we know that executive officials can do (a) or (b). Two FBI agents just happen to be outside a bank when they see a couple of guys rush out of the bank with guns and sacks of money, and jump into a car. Believing that they've just observed a bank robbery, the FBI agents pursue the two guys. Ask them later what they were doing, they'll say, "Trying to catch a couple of robbers." In the course of the pursuit, and still trying to catch them, they shoot out the escape car's tires -- in circumstances where it's really likely that the result will be a crash in which the (suspected) robbers will die. (That's case [a] above.) Does anybody really think that they can try to shoot out the tires only if they manage to call a judge and get authorization as the chase is going on? Or that, if they can't shoot out the tires without being sure that the (suspected) robbers will survive, they have to let the robbers get away?
Now, for case (b): The escape car is weaving in and out of heavy traffic, and the crashes it's causing are beginning to pile up, with lots of people being injured and some possibly dying (although the FBI agents can't be sure about that). To stop the carnage, the agents shoot out the escape car's tires, with only the faintest of hopes that the car's occupants will survive -- and, in fact, if you asked them later, they'll say, "We didn't care whether the robbers lived or died, we just want to stop them." Although some philosophers might quibble, I think we ought to say that, under those circumstances, they intended that the robbers die -- that is, they intended to kill them. (And, frankly, I don't think the philosophical quibbles have any real bearing on the drone/terrorist cases that people are exercised about. In the cases I'll describe, the executive officials either want to capture the suspected terrorists but expect that in the effort to do so the terrorists will die, or are indifferent to whether the terrorists live or die.)
The scenarios I've described have two characteristics: (1) The FBI agents have a high degree of confidence in the information they're acting on even though that information hasn't been evaluated by a judge -- or even, in the scenarios, by a supervisor in the FBI field office. But, a high degree of confidence isn't certainty -- maybe they've interrupted a staged scene for a movie, or some sort of weird prank. (2) There's a high degree of temporal urgency to taking action, so consultation with a judge is as a practical matter impossible. What's needed to support the OF COURSE answer are parallel characteristics in the terrorism case.
So, suppose the FBI has been conducting authorized surveillance (processed through a judge) on a domestic terrorist of the Terry Nichols sort. They've gathered a fair amount of information that leads them to suspect, with some confidence, that he's planning a terrorist bombing, but the quality of the information isn't quite good enough for them to be able to arrest him and be confident that prosecutors could secure a conviction. So, they're waiting for the last bits of information to come in. Unfortunately, they accidentally lose track of the suspect for a full day. Then they get a phone call from someone they relied on when they went to the judge for permission to wiretap, etc., who tells them that the guy's on the road right now in a van loaded with explosives, within thirty minutes of arriving at his target. The informant tells them the suspect's route and the intended target. That's enough to justify arresting the guy, but thirty minutes isn't enough time to lay the case out to a judge. So FBI agents do what they can to stop -- and arrest -- him. They might put up a roadblock on the route. If the suspected terrorist tries to run the roadblock, though, there's a very high chance that the van will blow up and the suspect will die (case [a] again). But, suppose there's no time to put up a roadblock, but there's time to put a sniper at the target site. As the van approaches the target, the sniper shoots the van driver. Again, I'm quite confident that the sniper and the FBI haven't violated the driver's constitutional rights -- even though, once again, there's some chance that the information they're acting on is wrong.
So, why hasn't the Obama administration said what I just did? Well, first of all, I think it has, when you put together all the statements they've made. They've talked about imminence, for example, in ways that make it clear that they're defining imminence in relation to the ability to arrest (or capture, when dealing with questions about terrorists outside the United States). Second, the more sophisticated critics have said they their primary concern is transparency, that they don't know the circumstances under which the administration believes it wouldn't violate the Constitution to target a US citizen on US soil. But, I doubt that the administration could fairly say more than something like this: "We think we can target people after we've done our damnedest to assure ourselves that the targets do in fact pose an imminent threat to domestic security, and when we've done the best we can to rule out the possibility that we can stop them by arresting them in circumstances where there's a relatively low probability of doing so safely." Ask for more than that, and all you'll get is, "Circumstances vary so much that we can't say anything more precise."
I'm allowing comments, and will update/respond if people point out problems with or gaps in what I've written.