Whether House Republicans will succeed in limiting the national government is a question raised by a simple rule adopted on their first day in the majority. Under the rule, every bill when introduced must be accompanied by a statement citing the specific authority granted to Congress by the Constitution under which it may pass the proposed law. Lacking such a statement, the bill will be returned to its sponsor.

The new rule was promised last September in the Republicans’ Pledge to America. Its appeal is evident. Americans extol the virtues of self-government, by which we mean constitutional self-government. That is, we govern ourselves under our Constitution, the “supreme law of the land.” Because members of Congress, like the president and members of the Supreme Court, take an oath to uphold the Constitution, it is fair to ask whether congressmen are living up to their oath if they pass a law without considering their constitutional authority to enact it in the first place.

Congressional Democrats (and some Republicans, too) have often been dismissive of the obligation to consider constitutional questions of legislative authority, thinking such questions should be left to the courts. The debate over the mandate included in Obamacare—that every American buy health insurance or face a penalty—is illustrative in both respects.

When House Speaker Nancy Pelosi was asked by a reporter “where specifically .  .  . the Constitution grant[s] Congress the authority to enact an individual health insurance mandate,” she seemed shocked by the question, and asked the reporter whether he was “serious.” In the Senate, meanwhile, Democrat Claire McCaskill responded to a question about the mandate’s constitutionality with the observation that, “if anything in this bill is unconstitutional, the Supreme Court will weigh in.” (The courts must be too slow for McCaskill, who faces reelection in 2012, as she recently voiced opposition to the mandate.)

Odd as it may seem to put this way, the Republicans’ new rule makes it okay for the House to take the Constitution into account in its deliberations. Of course, the mere citation of constitutional authority will not make a law constitutional. Nor will it oblige courts, exercising the power of judicial review, to declare a law constitutional. What advocates of the new rule hope is that it will lead to more discussion among members about the congressional authority to legislate, and that the House will take a more restrained understanding of its capacity, one more consistent with the Constitution’s original meaning.

It is useful to put this issue of legislative authority in larger perspective. What might be called the unlimiting of the national government began to take place during the New Deal, when the Supreme Court understood congressional authority to be so capacious as to leave little that Washington could not regulate. Congress largely accepted the Court’s jurisprudence and extended its legislative reach, losing sight of the core purposes of government and building our big and costly welfare state.

Against this development, the Court under Chief Justice Rehnquist eventually pushed back, though with only modest success. In 1995, in United States v. Lopez, the Court found that congressional power had become virtually limitless when President Clinton’s solicitor general was unable to identify any principle that might confine congressional regulation under the commerce clause. In Lopez, the Court struck down the Gun-Free School Zones Act on grounds that it exceeded congressional authority under the clause. Because of Lopez and a few other cases, there are some limits to what Congress constitutionally may legislate. If the individual mandate is upheld, there will be fewer.

The unlimiting of government, never so well understood until now, is what House Republicans are responding to. They have the numbers to defeat any bill that they believe Congress lacks the authority to enact, and by requiring bills to be accompanied by a constitutional authority statement, they are indicating their interest in doing precisely that. That the House may be willing to give up authority established by case law and historical practice is startling, indeed a development without precedent in our politics. But it is nonetheless an encouraging development, one that House Republicans will be pushed by the Tea Party to follow through on. As they should.