Damn. Now everyone thinks I hate on the libertarians. I don't, really. Libertarians have many principled, coherent arguments to offer in a piecemeal way. I even agree with quite a few: I don't think there should be subsidies or tariffs; I think people should be able to own guns; I think drugs should be decriminalized. Hell, I think that people ought to be able to practice gay polygamy. 'Do your own thing, man, as long as it doesn't hurt anyone else', as that one hippie guy in your undergraduate philosophy classes used to say. I'm perfectly willing to listen to arguments about how the state is performing some function badly and at a loss which someone else could perform better and at a profit. Up with private space exploration! Let's sell the moon to random technopreneurs!
Nonetheless, I also think it's fair to point out when people go off the rails. The proposed end-state of all this state-trimming can't just be no government at all. Minarchist libertarians, people who just wish the US government was 50% of its current size, (or 15%) -- fine. I'm sure we can have many fruitful arguments. Anarcho-libertarians are fruitcakes, though, and many of the things they believe seem to contradict some of the more compelling arguments for things libertarians hold dear. For example, I have been convinced that strong property rights are a good thing. Countries with weak property rights and a lack of contract enforcement languish economically and can't unleash their full potential -- people can't borrow against their farm land to buy fertilizer, commerce is restricted to trust-based, small scale operations. So, I'm afraid we need the government to enforce contracts and guard against violations of property rights, otherwise everything will go to hell.
Finally, I know that libertarians are sick of hearing about the Wild West (or the eastern Congo), but if you propose a model of rights enforcement whose nearest analogue seems to be the Clint Eastwood movie "A Fistful of Dollars", then you just have to suck it up. It can hardly be irrelevant or illegitimate to point out that in our world, which my people call "Earth", there already exist places where people must band together for self-defense and form militia-like organizations for private rights enforcement. In all these places, some bastard gets in charge of it and starts treating everyone like shit. Quis custodiet, etc. How do I fire my private-rights enforcement group again?
It's important not to fetishize the right of self-defense out of all proportion. I could be as heavily armed as I like, but I have to sleep sometime, and if I'm home alone with my children and fifty armed guys show up, I'm still screwed. Personally, I'd like to be able to call 911 and have the cops show up (I figure I could hold even 50 guys off that long, with a defensible position and a sniper rifle). In the libertarian utopia, those guys outside would be the cops. I know that there are places in the world where the cops are the bad guys. But this is a problem which we know, empirically, can be fixed. It seems to me there are insuperable, structural difficulties in proposing that private organizations take over all the functions of the state, which have to do with human nature. People will be bastards if you give them a chance. Stipulating this feature away does not make for good political practice. See: communism, passim.