In the latest Libertarian Papers, my long-time debate partner Walter Block adds a strange new epicycle to libertarian absolutism.  Suppose, he asks, that “all-powerful Martians would blow up the entire earth” if various libertarian policies were adopted.  He refuses to bite the bullet of advocating the Earth’s destruction, so he switches to a slightly different absolute moral theory:

I therefore propose an alternative, or, rather, a further explication of libertarianism. In this view, libertarianism becomes a theory of punishment, in its more well-developed format. Punishment for what? Why, of course, for the violation of the NAP.

We must cleave to some vestiges of traditional libertarianism in this new understanding of it. In this alternative dispensation, the libertarian would in effect say to the would-be murderer or rapist: it is a matter of irrelevance to us whether or not you engage in the acts you are now contemplating. Qua libertarians, we do not really care one way or the other.  However, if you engage in such acts, we will punish you to the full extent of the law.

Example:

The NAP, simpliciter, implies that never, ever should we oppose the legalization of drugs, no matter what the consequences. The more sophisticated version of libertarianism, punishment theory, states something very different. If the consequences are great enough in terms of rights violations, then, indeed, it is appropriate for a libertarian to oppose drug legalization, provided that those who oppose it are made to pay the proper penalty.

Similarly, if some libertarians oppose a tax cut in order to save the Earth from destruction at Martian hands:

[T]hose libertarians responsible for the rescinding of the tax reduction are guilty of a crime. They have in effect stolen the additional revenue that would have accrued to the long suffering tax payers, under the tax rate reduction plan. So, they must be punished, for violating the NAP. We first hold a ticker tape parade for these criminals, fete them all over the (grateful) world (since they have saved humanity). They were truly heroes, since, not only did they save us, but, as libertarians, they acted against the beloved NAP. But, then, given our new interpretation of libertarianism, we punish them to the full extent of the law, and, with their acquiescence! … Thus, as good libertarians, who are also utilitarians, they welcome their punishment. In this way, only in this way, can we eat our utilitarian cake, and keep our deontological cake, too.

My take: All absolute moral theories (except trivial theories like “Always do
the right thing”) are vulnerable to devastating counter-examples.  Block
himself quickly admits his punishment theory crumbles before a
revised version of his Martian hypothetical.  So instead of adding his weird epicycle onto libertarian absolutism, why doesn’t Block just switch to my common-sense position that libertarianism is only a presumption?