The New Deal made an unexpected appearance at the Supreme Court recently - in the form of a 1942 case about wheat. Some prominent states' rights conservatives were asking the court to overturn Wickard v. Filburn, a landmark ruling that laid out an expansive view of Congress's power to legislate in the public interest.

Supporters of states' rights have always blamed Wickard, and a few other cases of the same era, for paving the way for strong federal action on workplace safety, civil rights and the environment. Although they are unlikely to reverse Wickard soon, states' rights conservatives are making progress in their drive to restore the narrow view of federal power that predated the New Deal - and render Congress too weak to protect Americans on many fronts.

We take for granted today the idea that Congress can adopt a national minimum wage or require safety standards in factories. That's because the Supreme Court, in modern times, has always held that it can.

But the court once had a far more limited view of Congress's power. In the early 1900's, justices routinely struck down laws protecting workers and discouraging child labor. The court reversed itself starting in 1937, in cases that led to Wickard, and began upholding these same laws.

States' rights conservatives have always been nostalgic for the pre-1937 doctrines, which they have lately taken to calling the Constitution-in-Exile. They argue - at conferences like "Rolling Back the New Deal" and in papers like "Was the New Deal Constitutional?" - that Congress lacks the power to do things like forcing employers to participate in Social Security. Given how entrenched New Deal programs have become in more than half a century, these plans for reversing history have always seemed more than a bit quixotic.

But that may be about to change. The attacks on the post-1937 view of the Constitution are becoming more mainstream among Republicans. One of President Bush's nominees to the United States Court of Appeals for the Ninth Circuit, Janice Rogers Brown, has called the "revolution of 1937" a disaster. And last month in the Supreme Court - in a case about medical marijuana - the justices found themselves having to decide whether to stand by Wickard....

If the Supreme Court drifts rightward in the next four years, as seems likely, it could not only roll back Congress's Commerce Clause powers, but also revive other dangerous doctrines. Before 1937, the court invoked "liberty of contract" to strike down a Nebraska law regulating the weight of bread loaves, which kept buyers from being cheated, and a New York law setting a maximum 10-hour workday. Randy Barnett, the law professor who represented the medical marijuana users, argues in a new book that minimum wage laws infringe on "the fundamental natural right of freedom of contract."

In pre-1937 America, workers were exploited, factories were free to pollute, and old people were generally poor when they retired. This is not an agenda the public would be likely to sign onto today if it were debated in an election. But conservatives, who like to complain about activist liberal judges, could achieve their anti-New Deal agenda through judicial activism on the right. Judges could use the so-called Constitution-in-Exile to declare laws on workplace safety, environmental protection and civil rights unconstitutional.

Getting rid of Wickard would be an important first step....