Ron Paul told supporters at a campaign event on Tuesday that Medicare and Medicaid programs, through which the federal government provides health care to retired and poor Americans, are unconstitutional.

Paul, a U.S. representative from Texas and a candidate for the 2012 Republican presidential nomination, is known for his libertarian views. He said on Tuesday that there is no provision in the U.S. Constitution that authorizes the federal government to provide health care, and that the power to do so thus belongs to the states under the 10th Amendment.

The Supreme Court ruled in 1937 that Social Security was permissible under Article I, Section 8 of the Constitution, which reads in part, The Congress shall have power to lay and collect taxes, duties, imposts and excises to pay the debts and provide for the common defense and general welfare of the United States. Supporters of Medicare and Medicaid, which were established decades later as part of President Lyndon B. Johnson's Great Society legislation, hold that these programs are similarly permissible under the general welfare clause.

But in an interview in May, Paul told Fox News that this interpretation of the Constitution was an extreme liberal viewpoint that has been mistaught in our schools.

Article I, Section 8 doesn't say I can set up an insurance program for people, he said. What part of the Constitution are you getting it from?

The question, of course, is whether federal insurance programs like Medicare and Medicaid fall under the umbrella of general welfare -- and under current Supreme Court precedent, they do. But Paul said in his Fox News interview that the Supreme Court upheld slavery, too, and that a Supreme Court ruling doesn't mean something is actually constitutional.