A question has been going around on legal blogs -- "Does a Federal Mandate Requiring the Purchase of Health Insurance Exceed Congress' Powers Under the Commerce Clause?"
My answer is: Nowadays (not in the original intent) is there anything the Feds can do that exceeds current interpretations of the commerce clause? In Raich, the Supreme Court decided that a product (marijuana) that was grown in state for personal consumption, like tomatoes in your own garden, and was used legally under state law, can still be regulated under the commerce clause. As Clarence Thomas wrote in dissent:
Diane Monson and Angel Raich use marijuana that has never been bought or sold, that has never crossed state lines, and that has had no demonstrable effect on the national market for marijuana. If Congress can regulate this under the Commerce Clause, then it can regulate virtually anything and the Federal Government is no longer one of limited and enumerated powers
Unfortunately the theory that this personal use in California could somehow affect marijuana pricing in other states (by growing their own, they reduced demand for out of state weed which might affect prices in Arizona -- again similar to an argument that growing your own tomatoes might affect prices in another state) won the day in the Court. With the Supreme Court accempting this "butterfly effect" argument (because truly the demand of one person in a national market is like a butterfly flapping its wings in China and affecting a hurricane in the Gulf of Mexico), anything falls under the commerce clause.