The philosophical lexicon is an old and funny web resource, and one of the most famous entries on it is the rhetorical strategy of "outsmarting" a dialectical opponent:
outsmart, v. To embrace the conclusion of one's opponent's reductio ad absurdum argument. "They thought they had me, but I outsmarted them. I agreed that it was sometimes just to hang an innocent man."
It's in reference to J.J.C. Smart's famous concession that Utilitarianism does entail that consequence, and so it should be just to do so. In my department, we regularly make reference to the move. Your view about perceptual justification entails external world skepticism? Embrace skepticism – you never really know anything! This view about justice requires that some people can be made slaves? Embrace slavery as just – of course there are natural slaves! Congratulations, you just outsmarted your critics.
A new case of outsmarting was just sent along to me by a colleague. It goes like this. Suppose that an asteroid is heading toward earth, surely to destroy it. Does libertarianism make room for the use of tax money to be used to destroy the asteroid and save the world? Or would that be excessively paternalistic about how we want to meet our end? Or would it be theft, nevertheless? The Onion did a spoof on how Republicans would reject the plan on the basis of how the government's actions would get in the way of a free enterprise solution. That was parody, but Sasha Volokh, over at the Volokh Conspiracy, has a different sort of reason, but of the same spirit and leading to the same conclusion:
I don’t speak for all libertarians, but I think there’s a good case to be made that taxing people to protect the Earth from an asteroid, while within Congress’s powers, is an illegitimate function of government from a moral perspective. I think it’s O.K. to violate people’s rights (e.g. through taxation) if the result is that you protect people’s rights to some greater extent (e.g. through police, courts, the military). But it’s not obvious to me that the Earth being hit by an asteroid (or, say, someone being hit by lightning or a falling tree) violates anyone’s rights; if that’s so, then I’m not sure I can justify preventing it through taxation.
Crooked Timber's already made the Poe's Law observation about this (too bad, because Poe's my thing these days), but this does seem the sort of reduction to absurdity that should make the full-bore libertarian hesitate. Even J.J. Smart has a moment "which makes [him] wonder whether after all [he] really is a utilitarian." Volokh, too, notes that "this does make me uncomfortable." Yeah, me too.