The federal courts have long been viewed as democracy's watchdog. With the power to review the actions of elected officials, they can guard against the worst excesses of popular government. In this sense, it is often said, the courts are anti-democratic because they flout democracy's promise of majority rule.

But in his new book, The Most Democratic Branch, George Washington University law professor and New Republic Legal Affairs Editor Jeffrey Rosen takes issue with this conventional wisdom. According to Rosen, the courts are not a counter-majoritarian force defying popular will or protecting minorities from the tyranny of the mob.

Instead, Rosen claims, the courts have traditionally deferred to the national consensus of opinion on important issues of constitutional law, from freedom of speech to affirmative action to assisted suicide. Thus, rather than thwarting democratic views, the courts have mirrored them.

And this is a good thing, Rosen argues. As Alexander Bickel noted in his classic book The Least Dangerous Branch, federal judges are unelected and lack the power to enforce their rulings. They are therefore poorly equipped to take the lead on contested issues of social policy. Whenever they have tried - as with race-based school busing, Rosen claims - they have failed spectacularly.

Is Rosen Right? He Makes a Strong Case That Courts Follow Public Opinion

Rosen's book is the latest of several recent efforts by left-leaning scholars (Chicago's Cass Sunstein among them) to promote the virtues of judicial restraint. To the cynic, this trend might seem suspect, coinciding as it does with the emergence of a solid conservative majority on the Supreme Court: No wonder liberals want restraint when conservatives are in power.

But Rosen casts his argument as part of a long tradition of bipartisan judicial restraint stretching back to such distinguished writers as Learned Hand, Felix Frankfurter, and, of course, Bickel. In fact, until quite recently, Rosen argues, deference to majority rule was the prevailing creed of both liberal and conservative judges.

There is much truth to Rosen's claim. Just as the courts are hardly the enemy of family values that Fox News depicts, so they have never been the heroic defenders of individual rights that liberals imagine.

One need only recall Justice Holmes' opinion in Buck v. Bell upholding the forced sterilization of the mentally retarded - "three generations of imbeciles are enough," he wrote, with characteristic bluntness - to shatter that illusion. Not to mention the Court's approval, in Korematsu, of the internment of Japanese Americans during World War II, still one of the darkest moments in its history.

At the same time, some of the Court's most celebrated decisions were not as daring as is commonly assumed. Polls taken shortly after the Court's ruling in Brown v. Board of Education show that a slight majority of Americans supported the desegregation of the public schools, undercutting the view that the Court single-handedly rescued the country from the long nightmare of Jim Crow.

Rosen Properly Concedes the Court at Times Has Opposed Consensus

But have the courts been entirely submissive to the other branches of government? Not exactly, as Rosen concedes.

In some cases, the Supreme Court has opposed the president when he appeared to be acting without congressional support. Its decision in Youngstown Sheet & Tube Co. v. Sawyer, blocking Truman's seizure of the steel mills is one example; another is its recent ruling, in Hamdan v. Rumsfeld, that the military commissions established by President Bush to try Guantanamo detainees violate federal law.

On occasion, Rosen notes, the Court has even defied a national consensus. In addition to discussing school busing, Rosen explores at length the Court's ill-fated decision in Dred Scott, which struck down a law banning slavery in the federal territories, and what he regards as the failure of Roe v. Wade, which announced a broad constitutional right to abortion.

These adventures in judicial unilateralism have not ended well, Rosen argues. They have "tended to provoke backlashes that often undermine the very causes the judges are attempting to advance."

Rosen's Controversial Claim: Courts Should Continue to Track Majority Opinion

Which brings us to Rosen's most provocative - and debatable - claim: Not only have the courts traditionally deferred to majority will, he argues, but they should continue to do so.

"When judges vainly imagine they can save the country from democratic excesses that they alone can perceive, they often imperil their own legitimacy and effectiveness in the process," Rosen writes. "Therefore, far from threatening judicial independence, judicial sensitivity to the views of the president, Congress, and the American people has tended surprisingly to preserve it."

Rosen is no doubt correct that judicial restraint helps to preserve the credibility of the courts. But to what end? Credit is pointless unless it is occasionally drawn upon, and it is not clear that Rosen thinks it is ever appropriate for courts to set aside the will of a national majority. Even the Japanese internment decision seems to receive his reluctant approval.

And what of constitutional principles? Rosen spends little time discussing the merits of various decisions, focusing almost exclusively on their practical effects. The implication is that the merits are beside the point, perhaps because constitutional interpretation is hopelessly indeterminate. But one doesn't have to embrace the formalist view that there are objectively right answers to constitutional questions - rather than, say, better and worse interpretations, as Ronald Dworkin argues-- to feel uneasy with Rosen's excessive pragmatism.

Under his approach, the courts are little more than national pollsters, taking the pulse of the country and interpreting the Constitution accordingly. This is hard to square with the fundamental idea of a written constitution, which presumes that some principles cannot be changed even by a majority.

Rosen's approach is also at odds with the system of checks and balances the Framers relied upon to guard against abuses of power. Under the Framers' system, the three branches of government are pitted against each other to ensure that no one branch becomes too powerful. If the courts decline to participate in this competition, as Rosen seems to counsel, then the balance of power could become dangerously skewed. The federal courts are a branch of government, not just a barometer of opinion.

It's also not clear that most Americans want the courts to follow majority will. According to a CBS News poll taken last summer, 49 percent of Americans think the Supreme Court should consider only the legal issues when deciding important constitutional questions, while 42 percent think the Court should also take into account the public's views.

These numbers indicate that blithely following public opinion may actually undermine the Court's credibility. They also indicate, ironically, that if the Court were to follow public opinion about its own role in our system, then it ought to follow the law, not the national consensus.

The Largest Flaw in Rosen's Argument: Accounting for Brown v Board of Education

Perhaps the biggest strike against Rosen's argument is that it fails the Brown test. For the past fifty years, legal scholars have measured each new theory of constitutional interpretation and judicial review against the Supreme Court's school desegregation decision. If a theory can justify the Brown decision, it is viewed as at least plausible. But if a theory would require a different result in Brown - as would, for example, strict adherence to the original intent of the framers of the Fourteenth Amendment - then it is considered fatally flawed. The idea is that Brown is now a keystone of our system; any theory that would remove it would topple the whole structure too, and is thus untenable.

On the surface, Rosen's argument seems consistent with Brown. As noted above, because it seems that a majority of Americans actually supported the outcome, Rosen claims that the Court was correct to rule that segregation violates the Fourteen Amendment's guarantee of equal protection.

But what if more than half the country had, instead, opposed desegregation? Under Rosen's approach, a decision contrary to that consensus would have amounted to judicial unilateralism. And because he opposes unilateralism, Rosen would presumably have opposed Brown had public opinion been different.

The Brown test is, admittedly, not the only measure of a constitutional theory. And recently, even Brown has come under attack by some scholars who question whether the Court's decision was in the best interests of African-Americans. But Brown is still widely viewed as the Court's finest moment. In a society of shifting and sometimes uncertain values, it serves as a fixed star against which to navigate.

And ultimately, that is the problem with Rosen's approach: it reduces the Constitution to a recurring national referendum and discounts the possibility of transcendent principles that are not subject to popular vote. There can be no fixed stars when there is nothing above shifting popular opinion.

Rosen Is Correct, But Only to a Point: Courts Cannot Be Entirely Majoritarian

So yes, Rosen is right that courts must approach their task with humility and an appreciation for the limits of their power. But the Constitution, which was intended to place certain questions beyond the reach of ordinary politics, is too important to be turned over entirely to the will of the majority.

Between the judicial unilateralism that Rosen condemns and the extreme deference he embraces is a middle path -- one that is both sensitive to public opinion, and committed to upholding constitutional principles. That is the path the courts should follow.