Libertarians like to compare the state to the mafia, but this is unfortunately not accurate: if it were, we'd be a lot better off. Everything the state does wrong stems from its trying to be benevolent. The mafia isn't benevolent -- helpful if you have certain kinds of problems, but not benevolent. The state is very good at breaking things, or credibly threatening to, and not much else; I'd rather it play to this strength than try to be something it's not. Corporations, for example, would be a lot more circumspect about approaching it hat in hand for a loan if there was a tacit understanding that failure to provide value on the investment would result in the CEO getting his kneecaps broken.
(Update:
tinymammoth indirectly points me to
this short bit by Arnold Kling that puts the point with much less tongue-in-cheek.)