[mindcrime]

Are you confusing libertarianism with anarchism?

Not necessarily. When you get to the most radical edges of libertarianism, you find the anarcho-capitalist types who are (depending on who you ask) a type of anarchist. Libertarians who hold to a strict adherence to the "NIF Principle"[1] are opposed to most of what passes for law enforcement in contemporary society since it largely involves initiation of force and isn't for self-defense.

[1]: http://en.wikipedia.org/wiki/Non-aggression_principle