Taxation is to fund the government AND THAT IS ALL. No other legitimate purpose for taxation exists.
The fact is, if we as conservatives are to establish any credibility with respect to the protection of individual liberty, we must hold tight to this principle.
The use of the federal tax code to encourage some forms of economic activity and punish others is not only counterproductive from a revenue standpoint, it is morally indefensible. By engaging in this practice we are making supplicants out of otherwise economically sound producers in our economy (as in lobbying) and we are also restricting economic liberty – a form of tyranny which is unacceptable in a free society.
This applies to all forms of federal taxation, and not just the income tax. The federal gasoline tax, for example, is a tax on our liberty of movement throughout the country. It discriminates against those who choose to use automobiles; as such, the government is picking economic winners and losers based on behavior it likes and dislikes, or at least it is attempting consciously or unconsciously to influence economic behavior. This violates our liberty.
Furthermore, the evidence from international experience as well as our own indicates that progressive or confiscatory tax rates provides the government with LESS revenue than a tax rate applying equally to all citizens. As such, our tax policy serves to limit our economic liberty much more than to properly fund our government. This should be offensive to conservatives, and it is a first principle we must consistently, forcefully articulate if we are to deserve governance again.