Soon, I hope debates on the merits of targeted killing are taking place not only at universities, but inside the federal court system. The Obama Administration hopes to avoid that fate. Its lawyers would have us believe that targeted killing with drones is a state secret, or else a so-called political question that isn't properly decided by judges.

In Israel, a state with national-security challenges far greater than ours, the Supreme Court grappled with this same question. Do judges have any role to play in targeted killing? They didn't see it as a close question. They saw their role as determining "the permissible and the forbidden" in combat that implicates "the most basic right of a human being—the right to life." They affirmed that "non-justiciability cannot prevent the examination of that question." I suspect James Madison would find their approach more prudent than what the Obama Administration suggests. The administration would have us believe not only that they're empowered to kill an American in secret, but that after the fact, courts should refrain from judging whether the killing violated the right to life of the target.

Does anyone else think that's a recipe for abuses?

But legal doctrine is not my area of expertise. So I'd like to begin, instead, with a moral question: Is it ever okay for the U.S. to kill people with drones? "This is actually an easy question," Mr. Wittes once said, "since drones clearly enable more discriminating and deliberative targeting than do alternative weapon systems." I want to repeat that. He thinks that once you've decided to use force, drones could be the most moral choice, because they're more deliberative and discriminating.

That's an interesting standard.

It got me thinking: Is it ever okay for the U.S. to use biological weapons? Is that ever the most moral option? They're terrifying. A taboo surrounds them, and treaties prohibit their use.

And yet.

Imagine a remote al-Qaeda compound. Inside its walls are a few dozen adult bomb makers, their wives, and many scores of children. Explosives are everywhere. A drone strike or a firefight would cause the whole place to blow. But a U.S. scientist has an alternative: a biological agent that, if dispersed over the compound, would target, incapacitate and kill only the adult males. Only the militants—no one else. Would that discriminating bioweapon be the most moral option?

That's a hard question. On one hand, maybe you save a lot of innocent women and children. On the other hand, using a bioweapon would have implications that transcend any one discrete mission. Similarly, using weaponized drones has implications that go far beyond any one discrete strike. Let's think through some of them.

1) For a drone strike to be an option, the United States has to fund a drone industry to build its arsenal, negotiate leases for drone bases in various foreign countries—often non-democracies where the people do not want a drone base and would vote against it if they were afforded rights that we think of as universal. In building this drone fleet and the infrastructure to use it, America inevitably normalizes the notion of weaponized drones all over the globe, and it seeds an industry that is certain to contribute to the weapon's proliferation in the future.