In Federalist 31 Hamilton states that,
[T]he national government should possess an unrestrained power of taxation… A government ought to contain in itself every power requisite to the full accomplishment of the objects committed to its care, and to the complete execution of the trusts for which it is responsible, free from every other control but a regard to the public good and to the sense (consent) of the people… As in republics strength is always on the side of the people, and everything beyond this (conflicts on what can be taxed) must be left to the prudence and firmness of the people; who, as they will hold the scales in their own hands.
To summarize, we control what can be taxed.
In Article 1 Section 8 of the Constitution, “The Congress shall have power to lay and collect taxes… to pay of the debts and provide for the common defense and general welfare of the United States.”
The phrase “general welfare” can have many meanings. Today “general welfare” implies education, Medicare, social security, public transportation, public housing, food stamps, and the list goes on.
Under the Constitution, Congress has the power to tax in order to pay for these things. In Federalist 30 Hamilton says, “Who can pretend that commercial imposts are, or would be, alone equal to the present and future exigencies of the Union?” So from the jurisdiction of Article 1 Section 8 and the reasoning of Publius, an income tax is legal to provide for the “general welfare.”
I believe that “It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.” So personally, general welfare (as it is currently understood) be damned. An income tax is legal and the funding of the entitlement state is legal because “WE THE PEOPLE” are consenting to it.
If you like paying income tax then stop reading now. (I’m expecting no one does…)