This week, the Supreme Court measured Obamacare to see whether it fits within the confines of the Constitution. The big picture is whether the Constitution limits the behavior of the federal government to the plain meaning and historical context of the Constitution, or whether clever lawyers and politicians can interpret language in the Constitution so as to justify whatever Congress wishes to do. Does the Constitution mean what it says? Does it limit the federal government to the powers it has delegated to Congress? Or is it a blank check for Congress to do whatever it can get away with?

One of those delegated powers is the power to regulate interstate commerce. The language in the Commerce Clause authorizes Congress "to regulate" commerce among the states. When James Madison wrote that phrase, he and the other Framers were animated by the startling lack of interstate commerce among the states under the Articles of Confederation. This was the period after the Revolution and before the Constitution when the merchants and bankers who financed the Revolution also controlled the state legislatures. They were both creditors, because they had lent money to the state governments to finance the war, and debtors, because they now controlled the machinery of state government that owed them money.

What did they do? They were the original corporatists and crony capitalists. They formed cartels to diminish in-state competition, and they imposed tariffs to discourage out-of-state competition. Thus, in order to turn 13 mini-economies into one large economy, and to protect the freedom to trade, Madison used the word "regulate," which to him and his colleagues meant "to keep regular." So, the Constitution delegated to Congress the constitutional power to keep interstate commerce regular by prohibiting state tariffs, and it did so.

But Congress was intoxicated with its new powers, so it began to keep commerce regular by regulating the fares charged by ferries going from Hoboken, N.J., to New York City -- and the Supreme Court said yes. From there Congress regulated the wages of workers who produced goods that were put onto those ferries -- and the Supreme Court said yes. Then Congress regulated the wages, working conditions and methods of manufacture of facilities whose goods never moved in interstate commerce, so long as the economic activity generated by the production of those goods had a measurable effect on interstate commerce -- and the Supreme Court said yes.

This jurisprudence has resulted in the courts approving the congressional regulation of the thickness of leather in shoes, the water pressure in home showers, the amount of sugar in ketchup, ad infinitum. Wherever you go in the United States, it is impossible to avoid confronting federal regulation of human behavior unmentioned in the Constitution, but justified by Congress under the Commerce Clause. It will be necessary for the court to put a backstop on this absurd progression of congressional power in order to invalidate Obamacare's individual mandate.

The other line of Commerce Clause jurisprudence that the court will confront started with a farmer growing wheat exclusively for the consumption of his family during the Great Depression, and the feds ordering him to grow less wheat. He resisted that order, and his resistance led to an infamous Supreme Court opinion that upheld the feds' order. That 1942 case stands for the propositions that even infinitesimal economic behavior, even behavior that is not numerically measurable, even behavior that is not of a commercial nature, even behavior that does not move products across interstate lines can be regulated by Congress if, when all the similar behavior in the land is taken in the aggregate, it could have an effect on interstate commerce. This aggregation theory is the most anti-historical, hysterical, disingenuous, convoluted ruling in the court's history. But it is still the law today, and it will be necessary for the court to distinguish or to overrule this case, too, in order to invalidate the individual mandate.

Justice Antonin Scalia reminded his colleagues during oral arguments this week that the Constitution is the supreme law of the land and it means today what it meant when it was written and ratified. If Congress can compel you to buy health insurance because that's good for you and for the country's economic health, he asked, can it force you to eat broccoli? And if it can, what is the value of having a Constitution that was written to limit the government's powers?