Ancap seeks to socially apply many of the already-developed principles of economics. The premise of ancap is the non-aggression principle, thus it recognizes the inherent illegitimacy of all government. The problem most people have with ancap is that it necessitates suffering of the weak. If the US were to suddenly go ancap there would be a long period of the weak dying off, a "purge" if you will.... but what people don't understand is that the resulting society would be almost utopic.