Anwar Al-Awalki, an American citizen affiliated with al-Qaeda, has been killed in a drone strike. This has set off a torrential debate about the legality of such strikes.
What's odd is that there is something worrisome about Al-Awalki -- but not what's getting most of the attention. It's not that he's a citizen. It's not that he was killed. It's rather a deeper lacuna in the laws of warfare and how they work (and don't work) in international conflicts against an enemy like al-Qaeda.
Let's start at the beginning, though. The argument being put out by folks like Glenn Greenwald is that liberals who were deeply concerned about President Bush's detainment policies should be apoplectic now that Obama has killed a man. There's obviously something intuitively plausible about this (killing is more serious than even indefinite imprisonment), but as a matter of law I think it's rather obviously wrong. In an armed conflict, the right of a party to kill opposing combatants is not controversial (it is subject to many restrictions, but none relevant here); however, if the combatant is captured, a plethora of new legal obligations open up.
Take a very uncontroversial example: The United States and Germany are engaged in a conventional war. An American soldier sees a German soldier. He shoots and kills him. Obviously, there is no legal problem with that. That's just war. One doesn't need a warrant or a trial, or even give an opportunity to surrender. On the other hand, if the soldier is captured, then a great many legal protections open up. One cannot, for example, summarily execute the person whom 10 minutes ago one would have had every legal right to kill. In fact, if one wants to charge them with a crime or impose any sort of punitive sanctions (POW confinement is considered non-punitive and for that reason standards attached to it are relatively generous), one has to afford considerable procedural protections. This, of course, is reflective of the peculiar status of war: it's legally sanctioned killing of individuals who have probably not committed (much less been convicted of) a crime.
Notably, nothing in the above argument turns on whether the German soldier was an American citizen or not. And it's not clear why it should -- a citizen who is engaged in armed conflict for a foreign party should, in the midst of such hostilities, be treated as a member of that armed group. And that seems reflected in both the letter and structure of the relevant law. First, as Matt Yglesias observes, one can lose one's citizenship already by "Entering or serving in the armed forces of a foreign state engaged in hostilities against the U.S." (8 U.S.C. 1481(a)(3)) -- it is more or less a failure of updating that this doesn't encompass non-governmental military actors engaged in hostilities against the U.S.. Second, in Ex Parte Quirin, 317 U.S. 1 (1942), the Supreme Court in fact directly dealt with a situation where a German belligerent was also an American citizen.* Third, the Fifth Amendment doesn't restrict itself to citizens anyway (rather encompassing "persons") -- and that's good, for (as I'll explain below), the real worries about operations like this don't really become any less significant if the target is a non-citizen.
Andrew of Coffee House Talks tries to argue that because the Constitution carves out a specific crime of treason, an American citizen effectively can't be a military belligerent but must be charged with that particular crime. This is simply wrong: one can both be a combatant subject to the rules of warfare and a traitor. As explained above, once captured a person who has allegedly committed treason must be afforded constitutionally required procedural protections; but that does not mean they are somehow exempted from the normal (non-criminal) rules of war (the upshot of Andrew's argument is that every shot fired by the Union in the Civil War was illegal).
So the problem isn't that Al-Awalki was killed. And the problem isn't that Al-Awalki's a citizen. So what is the problem?
Two spring to mind. The first is whether Al-Awalki actually was a belligerent. Recall that this is basically the same worry that was most salient about the Bush administration's detainee policy -- there is no problem detaining actual enemy belligerents and neither is there a problem killing them, but there is a huge problem about doing those things to random innocent schmoes. But with Al-Awalki the controversy isn't really about that: nobody seems to dispute he was part of al-Qaeda, rather, the controversy seems to stem from his supposedly non-combat role. Now, as I understand it one can be part of an armed group while serving in a non-armed capacity (e.g., a radio operator or a quartermaster) and still be a valid target. But this is an area, though, where I simply don't know the relevant facts about Al-Awalki's role.
In any event, at best I can say that while Al-Awalki may not be the troublesome case, we can easily imagine a situation where the target denies being involved with al-Qaeda at all. And then we have a problem. In normal war, you know who the enemy is -- they wear a uniform. In fact, it's a breach of the laws of war not to. And that's because we want to make sure we can easily distinguish valid military targets from bystanders. But of course, al-Qaeda does not operate like that, and that makes things considerably more complex. We can say this is one more thing dickish about al-Qaeda and other terrorist organizations who do not distinguish themselves from civilian populations, but (while that's 100% true), it doesn't actually resolve the problem.
The second problem is that the above analysis does not have a spatial restriction. It could easily apply to alleged al-Qaeda belligerents on American soil. And this is difficult. On the one hand, it can't be the case that once someone reaches American soil, we have to treat them as a criminal and not a belligerent (see, e.g., the Civil War, and Quirin for that matter). On the other hand, if Al-Awalki had stepped off the plane in New York City, I think we'd all agree the proper response is to try and arrest him, not shoot him in the face.
The best answer I can give is that in areas where America exercises police power (i.e., American soil), there should an extremely high presumption in favor of using the police power to arrest alleged enemy belligerents, excepting only if they are currently engaged in hostilities. I don't know if a presumption of that variety is encoded in current positive law (the Posse Comitatus Act comes closest). But there are certainly excellent prudential reasons to prefer this -- aside from the importance above of ensuring we get the right guy, where do get said guy there's more intelligence to be gained from a live mind than a dead body.
* The citizen (Haupt) was executed. I think Quirin is problematic, not because Haupt was a citizen, but because once the belligerents were confined the procedural protections accorded were too lax.