Most libertarians oppose the current income tax system. Is this because the system is too complicated and the IRS has a poor history, or because income taxes are inherently bad? What type of taxation system would be best? What type of taxation system would be best at the state and local levels?
Libertarians do not advocate the initiation of force, fraud, or theft to achieve social or political goals. If you refuse to contribute to my favorite charity, and I took your money at gunpoint anyway, I'd be stealing from you. Similarly, if I vote for taxes to force you to contribute to that charity through taxes, I'm asking the government to take your money -- at gunpoint, if necessary.
What is wrong for me as an individual, is wrong for a group of individuals acting through 'government.' Wrong doesn't turn into right, just because the majority agrees to it. Minorities have no protection if they have to depend upon the majority for it.
As a result, libertarians believe that ALL taxation is theft. Libertarians believe that the services supported by taxes can be provided more economically and efficiently by the private sector.