“If men were angels,” James Madison once wrote, “no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary.”

America’s founders truly understood the nature of both human beings and the governments they create. These are two sides of the same coin and mean that the ordered liberty we enjoy requires limited government. At no time is that principle more necessary than in the current debate over healthcare reform.

The genius of our Constitution is that it both empowers and limits government in general, and the federal government in particular. The Constitution delegates what Madison called “few and defined” powers to the federal government and enumerates, or lists, them.

Congress must have more than just a good idea or a noble intention to legislate; it must also have authority grounded in at least one of those enumerated powers. That way the political ends do not automatically justify the constitutional means and our liberty can stay intact.

Each of the current health care reform bills would require everyone to buy health insurance. Even if this were the best idea in the entire history of ideas, we must ask whether Congress may do it before considering whether it should do it.

The Constitution must come before politics. The only enumerated power that could conceivably justify this individual mandate to purchase health insurance is Congress’ power to regulate interstate commerce.

The Supreme Court has steadily expanded the meaning of “interstate commerce” as the category of what Congress may regulate. During the 19th century, the Court said it includes such things as “the purchase, sale, and exchange of commodities” between citizens of different states.

That changed significantly by the early 1940s, especially after President Franklin Roosevelt began appointing Justices with a more flexible approach to the Constitution’s meaning. The Court broadened Congress’ power to include regulating any activity – even non-commercial as well as intra-state activity – that substantially affects interstate commerce. That remains the basic definition today.

But there has been one constant since the Constitution was first drafted. Every Supreme Court commerce

clause case has involved Congress attempting to regulate some activity in which people had chosen to engage. In other words, Congress sought to regulate how, but not whether, people did things that either were, or substantially affected, interstate commerce.

The mandate that individuals buy health insurance is exactly the opposite of this unbroken pattern. It is a difference in kind, not a difference in degree. This mandate would, for the first time, use the commerce clause to cross the line between regulating what people do and start requiring what people must do. Regulating commercial transactions is one thing, requiring them is another.

There is something of an unpleasant deja vu here. The Clinton administration’s attempt at health care reform included an almost identical mandate that individuals purchase health insurance. In August 1994, the Congressional Budget Office concluded that this “would be an unprecedented form of federal action. The government has never required people to buy any good or service as a condition of lawful residence in the United States.”

Nothing has changed. Just a few months ago, the Congressional Research Service said in a report that “it is a novel issue whether Congress may use (the commerce clause) to require an individual to purchase a good or a service.”

If it may, then there was really no need for the “Cash for Clunkers” program because Congress could simply have ordered people to buy fuel-efficient cars. There was no need for the TARP or other bailout programs because Congress could have ordered people to buy certain stocks or deposit their money in certain banks. Incentives are one thing, mandates are another.

Eliminating the element of individual choice would be boldly going where Congress has never gone before. And by eliminating virtually any limit to federal government power, it would do irreparable damage to individual liberty.

The front steps of the National Archives bear the words “eternal vigilance is the price of liberty.” Those words are appropriate for the home of the Constitution. Vigilance requires applying the Constitution’s principles to guide and, if necessary, to limit what government does, even with something as important as healthcare reform.

The Constitution does not, it cannot, mean whatever government wants it to mean or there would no limits left on government power. Congress may not be able to do everything it wants to do, but that is indeed the price of liberty.

Sen. Orrin G. Hatch, R-Utah, is a senior member of the Senate Finance Committee.