Over the last fifty years, Americans have grown accustomed to viewing the Supreme Court as the main guarantor of the rights protected by the Fourteenth Amendment. The Amendment provides that a state may not "deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."

In requiring states to respect free speech, personal privacy, and various principles of fairness, the Supreme Court has relied on the Fourteenth Amendment's Due Process Clause. In prohibiting nearly all forms of race discrimination and most forms of sex discrimination, the Court has relied on its Equal Protection Clause.

Yet when the Fourteenth Amendment was enacted in 1868, it was expected that Congress, not the Supreme Court, would play the principal enforcement role. Recall that barely a decade earlier, in 1857, the Court had decided the infamous Dred Scott v. Sandford -- invalidating the Missouri Compromise on the ground that Congress lacked constitutional authority to confer citizenship on African-Americans.

With this experience in mind, the Reconstruction-era Republicans who proposed the Fourteenth Amendment did not trust the Court to protect the rights of then-newly-freed slaves. Thus, Section Five of the Amendment provides that "Congress shall have power to enforce, by appropriate legislation, the provisions of this article."

The Rehnquist Court appears to have forgotten this history. In case after case over the last four years, the Court has mandated its own narrow conception of the rights protected by the Fourteenth Amendment, rejecting Congress's broader one. That is unfortunate, not only because it disserves the Amendment's historical purposes, but also because it undermines fundamental principles of democracy.

In 1997, in City of Boerne v. Flores, the Court invalidated the Religious Freedom Restoration Act ("RFRA"). That statute provided that if a formally neutral state law placed a substantial burden on a person's ability to practice his religion, then the person was entitled to an exemption from the law, unless the state could demonstrate a compelling reason for overriding religious freedom.

Congress had passed RFRA as a response to the Supreme Court's earlier decision in Employment Division v. Smith, handed down in 1990. Smith had permitted the state of Oregon to apply its general anti-drug law to ritual peyote use by Native Americans. An overwhelming majority of Republicans and Democrats in Congress believed that Smith gave inadequate protection to members of minority faiths. (Formally neutral laws like those prohibiting peyote use but permitting alcohol consumption often favor majority religions: Ceremonial wine may be used, but not ceremonial peyote.)

But the Supreme Court disagreed, ruling that Section Five of the Fourteenth Amendment only gives Congress the power to enforce the Court's understanding of substantive rights, not Congress's own. According to the Court, formal religious equality was all that was required — no matter that formal equality's effect is to permit majority religions' ceremonies, and effectively forbid some minority religions' ones.

Over the past two years, three more blows to Congress have come in quick succession. Last year, in Kimel v. Florida Bd. of Regents, the Court ruled that Congress exceeded its power under Section Five when it forbade age discrimination by the states.

In applying the Equal Protection Clause, the Supreme Court has articulated categories of presumptively invalid discrimination, termed "suspect" and "quasi-suspect classifications." The Court's list includes race, national origin, and sex, but not age. Thus, when Congress sought to add age to the list, it was rebuffed. Once again, the Justices preferred their own conception of Fourteenth Amendment rights to that of the national legislature.

Also last year, in United States v. Morrison, the Court invalidated a provision of the Violence Against Women Act ("VAWA") that gave victims of gender-motivated violence the right to sue their attackers. Relying on the 1883 precedent of the Civil Rights Cases, the Court said that the Fourteenth Amendment does not reach private conduct — even though Congress believed that VAWA was needed to remedy deficient government conduct: to wit, the states' failed efforts at combating gender-motivated violence.

Finally, this year, in Bd. of Trustees of the University of Alabama v. Garrett, the Court struck down the portion of the Americans With Disabilities Act that provided a damages remedy against the states. The Court applied the logic of Kimel — reasoning that since disability is not on the Court's own, limited list of suspect classifications, Congress cannot add to the list, and use the Equal Protection Clause to remedy disability discrimination. This, despite Section Five's specific mandate to Congress "to enforce, by appropriate legislation" the Fourteenth Amendment.

Most of the cases narrowly construing Congress's Section Five power have been decided by a 5-4 margin, with the Justices favoring states' rights in the majority. Why have these Justices been willing to substitute their view of the Fourteenth Amendment for Congress's view?

Surely it is not ignorance of history. Chief Justice Rehnquist, for example, who votes in the majority in each of these cases, is a history buff, with a deep knowledge of the Civil War and Reconstruction eras.

The Court has nonetheless been willing to arrogate to itself primary responsibility for interpreting the Fourteenth Amendment because the Justices do not trust Congress. Virtually any human activity can threaten life, liberty, property, or equality. Thus, under the guise of "enforcing" the Fourteenth Amendment, Congress might regulate any human activity. That, in turn, would violate the Tenth Amendment principle that the federal government is one of limited powers. Accordingly, the Court has limited Congress to enforcing the Court's own understanding of the Fourteenth Amendment.

There is some logic to this position. Republicans and Democrats alike are loath to oppose bills promoting "Religious Freedom" or combating "Violence Against Women." It is difficult for a Congressman or Senator to explain in 30-second advertisements that he supports such policies but only at the state or local, rather than the national, level. So with Congress's members apparently unwilling to take the Constitution's limits seriously, five Justices have tried to do the job for them.

Nonetheless, the majority Justices' position is untenable. As a matter of pure political theory, we might expect Congress to continually expand its regulatory power until that power is all-encompassing. But in fact, it has not.

Consider civil rights legislation. Under the majority Justices' view, Congress should have attempted to expand discrimination law to protect any and all interest groups. In fact, Congress has not expanded the categories of suspect discrimination nearly as far as some states have, in their discrimination statutes. (California, for example, makes all arbitrary discrimination illegal.) By contrast, national civil rights legislation has been enacted only in the wake of an emerging national consensus — one that has added age and disability to the traditional lists of characteristics that should not be the basis for distributing employment and other important opportunities.

Moreover, given the powerful influence of states and business interests in Congress, if anything, one would expect too little rather than too much in the way of civil rights legislation, in light of the inevitable costs to state governments and businesses of compliance with — and lawsuits arising from — civil rights laws.

The Supreme Court's own doctrines suggest an alternative to the Court's recent hostility to civil rights legislation. In another context, the Justices have often said that the Eighth Amendment's prohibition on "cruel and unusual punishments" incorporates "the evolving standards of decency that mark the progress of a maturing society." To give content to those standards, the Court has looked to whatever consensus can be found in laws enacted by democratically elected legislatures.

The Court might take a similar view of the equally ambiguous language of the Fourteenth Amendment. Once the Justices have established a constitutional floor — prohibiting, for example, de jure racial segregation — they could look to Congress's judgment to fill in additional details about such matters as what forms of discrimination our maturing society considers most invidious.

The recent cases narrowly construing Congress's Section Five power, discussed above, have required that Congress's laws be "congruent and proportionate" to the Court's doctrines. But invalidation of Congress's work is not the only way to achieve the goal of congruence and proportionality. If, instead, the Court were to adjust its doctrines to Congress's work, congruence and proportionality would also be achieved — in a manner that respects the Fourteenth Amendment's historical purpose and Congress's ability to identify shared national values.