You have to admire the sheer gall of a man who defends compulsory national service on libertarian grounds. Pascal-Emmanuel Gobry does so in this month’s Cato Unbound. What really got my attention was this bit:
Libertarians think it’s legitimate for the state to use violence to take people’s money. If you don’t think taxation is legitimate, you are an anarchist, not a libertarian.
Well, military service is a form of in-kind taxation. Money is time. That’s what it is. When I buy a loaf of bread, I exchange a little bit of my time for a little bit of the baker’s time.
Perhaps it’s only legitimate for the state to take our time in the form of money and not in its original form, but we know that it’s not true.
Oh really?! When libertarianism really emerged as a distinct political force in the 1970s, it was thought that libertarianism excluded taxation that was not consented to (so homeowners’ association fees would be fine, for instance). The Libertarian Party platform long called for the abolition of taxation (and may still). Indeed, Robert Nozick argued that taxation is wrong for the same reason that slavery (“compulsory service”) is wrong. (Not, note, that taxation is morally equivalent to slavery or a species of slavery.) Gobry seems to accept Nozick’s claim that if slavery is always wrong, taxation is also always wrong, but by denying the consequent, is able to deny the antecedent.
But the bottom line is that you don’t have to be an anarchist to think that non-consented-to taxation is always impermissible.
PILEUS 
Gobry’s piece is a mix of truth and falsehood, but the critique of conscription as slavery is exagerrated. Slaves have zero rights. No voting rights, no right to trial by any kind of court, no right not to be tortured, etc. Conscripts have far more rights than this, in Western societies.
As for Gobry’s case, Hitler would’ve eventually subdued Switzerland if he’d beaten the Allies, if by no other means than cutting off its coal supply. Athens is not the great ancient Greek example of hoplite rule, that was Sparta, or perhaps Thebes. The Athenian Golden Age was the result of expanding voting rights to all Athenian males who could serve in the Navy, which didn’t require them to be able to afford their own panoply. And the Athenian Navy was built with the silver from the mines owned & operated by the Athenian government. It was precisely the Athenian deviation from the hoplite-ruled Spartan model that led Socrates and Plato to criticize the Athenian form of government. America had conscription during its biggest and bloodiest wars: the Civil War, WWI, WWII, & the Korean War. Somehow, that didn’t result in enough of anti-war movement to stop those wars; the Vietnam War remains a unique case for reasons of its own.
As for the rest of his argument, yes, support for compulsory schooling IS libertarian heresy; the same goes for most of the rest of his analogies.
I agree conscription is not nearly as bad as slavery. (And I can also imagine far-fetched scenarios in which conscription would be justified.) But slavery itself is a kind of continuum; you could imagine regimes ranging from zero rights to some rights to something more like modern conscription.
Great points about Athens vs. Sparta as well. Sparta should be no libertarian’s idea of a free society.
Yeah, I thought the errors exceeded my ability to count them.
Cato Unbound is meant to encourage discussion, it’s not giving official Cato positions. However, I can just see this being used as ammunition for big government types saying “Hey, even libertarians support it.”