When Justice William Brennan resigned suddenly in July, the initial liberal reaction was outright panic. Time, and the concentrating effect of our near-war in the Persian Gulf, have muted the panic. Reason and decorum will reign during the hearings for Brennan's successor, David Souter. But beneath the forced calm lies a deep anxiety that with Souter casting the deciding vote the liberal achievements of 30 years are about to be lost.

This anxiety is expressed as a complaint that the Supreme Court is about to lose its ideological "balance." Well, that's what happens when you lose five of six presidential elections. And when you run candidates like George McGovern and Michael Dukakis.

Democrats do, however, retain enough political strength to impose the Bork Rule: conservative Supreme Court nominees must be nonentities. Nonentities can, of course, surprise you and become entities. Anwar Sadat and William Brennan spring to mind. But these are triumphs of accident over design.

Every conservative jurist now knows that unless he maintains decades of radio silence about everything he believes, he has no hope of achieving the highest rank of his profession. A few weeks after the Bork affair, the editor of a scholarly journal (on foreign policy, of all things) told me that two of his authors, both lawyers, had asked that articles they had submitted to him be withdrawn. They did not want these particular views left on a paper trail. Hence the Bork Corollary: publish and perish.

This vow-of-silence rule is a loss for political discourse. The nonentity rule is a loss for excellence in the judiciary. Liberals, however, are concerned about other losses. They fret that darkness is about to descend on the constitutional rights minted by the Warren and Burger courts.

The fear is exaggerated. These rights, such as abortion rights, are unlikely to be lost. At worst -- if, for example, Souter uncharacteristically votes to overturn precedent and reverse Roe v. Wade -- their adjudication will be shifted to a different venue, the legislatures. Where they are likely to be sustained. It is highly unlikely that a majority of Americans will vote to ban abortion or roll back (non-quota) civil rights protections. A TV generation that knows the Miranda warning by heart is not about to rush to repeal it.

There is, however, a different and more profound significance to the changing nature of the court. The Founders established an intricate and manifold system of checks and balances designed to prevent tyrannical power. First, the political check of divided powers: the three branches of government contending with each other. Then the geographical check of federalism: the states contending with Washington.

And now we can perceive a third check that even the Founders, in their wisdom, did not foresee: the historical or intergenerational check. Supreme Courts, appointed by presidents long gone, register the values of 10, 20 and 30 years ago. They pit the majority values of the past (as represented in the political preferences of the presidents who appointed them) against the majority values of the present (as represented by the political preferences of the current president and Congress).

Thus Franklin Roosevelt was constrained by the conservative court he inherited, so much so that he was driven to try to pack it with liberals. He was too hasty. The fullness of time and the popularity of the New Deal took care of that. Over the years, the presidents of the liberal ascendancy (Roosevelt through Johnson) produced, through their cumulative appointments, a liberal court. And that court, the institutional memory of a liberal past, checked and challenged the conservatism of the Nixon-Reagan-Bush era.

Now another turn of the wheel. The Nixon-through-Bush appointees constitute a majority of the court. For decades to come, they will be a check on the coming liberal resurgence.

Of course, the coming liberal resurgence may never come. The Democrats have a demonstrated talent for losing elections they should have won. Nevertheless, it is safe to assume that conservative hegemony over the White House cannot continue indefinitely. And when the Democrats do regain the presidency, they will find themselves checked and challenged by a court embodying the values of the conservative '70s and '80s.

This will come as no consolation to the abortion-rights activists and civil libertarians who fear the worst from Souter. But it might calm the anxieties of those less ideologically committed but troubled by the claim that there is something radical and abnormal about an ideologically unbalanced court.

Such courts are as American as cherry pie. And by playing the values of the past against those of the future -- by allowing one political generation to keep watch on its children -- they create the most subtle and useful check of all.