The liberals who have jumped so enthusiastically into the battle to deny confirmation to Judge Robert Bork don't seem to realize it, but they are fighting yesterday's battles. And if they are so unfortunate as to win, they risk losing tomorrow's legal-political wars.

Bork, I think it is fair to say, is the closest thing we have to a principled believer in judicial restraint -- the idea that courts should overturn laws passed by legislatures only when the law violates an absolutely clear constitutional provision. His attackers do not really contest this proposition. Liberals don't like him because they fear he would refuse to overturn laws they don't like, notably anti-abortion laws; they don't claim he would overturn laws they favor.

If that's so, then Bork is exactly the kind of justice liberals should want. Right now, and probably for as long as the 60-year-old Justice Bork can be expected to serve, judicial restraint works for the liberals on most issues. American courts are mostly conservative. American legislatures are mostly liberal. Once it was the other way around, and it was in liberals' interest to make courts more powerful and legislatures less powerful. But today liberals have no reason to look for justices or doctrines to overturn what legislatures do. They should be looking for justices and doctrines that will let legislatures' acts stand.

It may not be obvious that legislatures are liberal today, especially to those in the warren-like backrooms of Washington liberal lobbies who imagine American legislatures are peopled mostly with Klansmen and Jerry Falwells. But 61 percent of legislators are Democrats, and they usually choose liberal leaders. Here in Congress, Jim Wright -- a committed liberal on economics, the only national politician gutsy enough to speak out for a tax increase, and alert to civil liberties as well -- succeeded Tip O'Neill as House speaker. In California, Willie Brown, a brilliantly skillful black from San Francisco, is speaker; New York's speaker is a liberal Jew from Brooklyn, Melvyn Miller; Pennsylvania's is Leroy Irvis, a black from Pittsburgh. Speakers George Keverian of Massachusetts, Vern Riffe of Ohio, Gary Owen of Michigan, Michael Madigan of Illinois, Tom Loftus of Wisconsin, and Jon Mills of Florida are all Democrats, liberals on most issues, and sharp political operators to boot. Bill Hobby, who runs the Texas senate, is the main force there for spending more on education and welfare. And so on in smaller states; but we've already covered the states where most Americans live.

Compare these legislatures with the courts. Most federal judges now are Reagan appointees, and while the balance would be changed if a Democrat won in 1988, that's not a sure thing. The recall by a 2-1 vote of Chief Justice Rose Bird has left the California courts in the control of political conservatives for the first time in 50 years. Mario Cuomo in New York has followed a policy of not appointing judges to further any liberal ideology. In the law schools the backers of liberal judicial theories are on the defensive, and much of the new debate is on the right. The argument there is whether judges should overturn laws passed by the legislatures as violations of economic liberty. On that argument Judge Bork is clearly identified as one who wouldn't overturn such laws.

But the liberals who are arguing against Bork aren't thinking about the cases seeking to overthrow the liberal laws of tomorrow. They're talking about decisions overthrowing the conservative laws of yesterday. (Most ludicrous is the argument, advanced even by The New York Times, that Bork might reverse the 1965 decision overturning the Connecticut law that banned contraceptives. That's a danger only if you think that some legislature is about to pass a law banning condoms -- not terribly likely at a time when many think condoms are our front-line protection against AIDS.)

Foremost among liberals' concerns is abortion. It was the pro-choice groups which first loudly attacked Bork and whipped the Democrats into line; the National Abortion Rights Action League snapped its fingers and Joe Biden, doing what he said he'd never do, jumped. The pro-choice crowd fears, realistically, that Bork would vote to overrule Roe v. Wade, the 1973 decision that overturned all state anti-abortion laws. We would be back, Edward Kennedy says, to the days of back-alley abortions.

This is nonsense. The voters don't want abortion outlawed, and the mostly liberal legislatures are not going to vote to outlaw it. About a dozen states today pay for Medicaid abortions for the poor; they're not likely to turn around and ban abortion for everyone. Even in the supposedly dark ages before Roe v. Wade, legislatures were moving rapidly toward legalization. In the five years before the decision, legislatures in 18 states with 41 percent of the nation's population liberalized their abortion laws, often to the point of allowing abortion on demand. On the day the decision came down, about 75 percent of Americans lived within 100 miles of a place where abortions were legal. Other legislatures would surely have liberalized their abortion laws in the legislative sessions just beginning as the Supreme Court spoke. (Bob Woodward and Scott Armstrong in their book, "The Brethren," report that Justice Potter Stewart, influenced by his daughter, felt that few legislatures seemed likely to amend their abortion laws. On this political judgment he couldn't have been wronger; the legislatures were acting more rapidly on this issue than they have on almost any issue in 200 years of American history.)

Today the liberals who suppose that legislatures will put abortionists in leg irons are just as wrong -- as the right-to-lifers are beginning to realize, with a sinking heart. A decision overruling Roe v. Wade would make pro-choice lobbyists work harder in state legislatures, which is where Justice Brandeis used to say liberal reformers should be busy working, and would force a lot of state politicians to take a stand on an issue they'd prefer to straddle. But that's what lobbyists and politicians are paid for.

Bork is not going to vote to overturn the Civil Rights Act (though he may say it means what it says and what Hubert Humphrey said it meant: that it forbids racial quotas), he is not going to overturn laws that can't be justified by free-market economics (as Judge Richard Posner would), and he is not going to overturn the graduated income tax or welfare programs (as University of Chicago professor Richard Epstein might). He is not going to write opinions that give thousands of conservative and sometimes just plain stupid state and local judges a warrant to overturn laws they don't like. The liberals are not likely to be granted another Reagan appointee who would be better for them than Bork. They should hope they're lucky enough to lose their fight to block his confirmation.

The writer is a member of the editorial page staff.