A critical question Supreme Court nominee Robert H. Bork will face during his confirmation hearings is whether as a justice he would vote to overrule the dozens of court decisions that he has spent his professional career condemning.

Under a centuries-old tradition of English common law known as stare decisis -- Latin for "to stand by that which was decided" -- courts are reluctant to upset their own precedents because of the importance of having settled, predictable legal principles.

Retired justice Lewis F. Powell Jr., whom Bork has been named to replace, said in a 1983 abortion case that stare decisis is "a doctrine that demands respect in a society governed by the rule of law."

The Supreme Court has sometimes decided it erred in an earlier decision -- perhaps most notably in Brown v. Board of Education in 1954, which overruled the "separate but equal" principle set forth in Plessy v. Ferguson in 1896. By conservative legal scholar Bruce E. Fein's count, the court has overruled nearly 300 of its precedents.

The issue for a number of senators weighing the Bork nomination is whether the 60-year-old jurist would vote to add dozens to that list.

More than any other Supreme Court nominee in recent memory, Bork has made clear that he thinks the high court strayed far beyond its constitutional bounds in deciding an array of issues. A study released yesterday by the NAACP Legal Defense and Educational Fund Inc. and People for the American Way listed 31 "major lines of precedent with which Judge Bork has disagreed."

The roster includes Supreme Court rulings finding that a constitutional right to privacy protects a married couple's right to use contraceptives and a woman's right to have an abortion; extending the Equal Protection Clause to cover discrimination against women, aliens and illegitimate children; and invalidating poll taxes, racially restrictive covenants and mandatory sterilization of criminals.

Bork has also criticized Supreme Court decisions upholding affirmative-action programs, supporting newspapers' right to publish the names of rape victims, and finding that the First Amendment protects pornography and offensive speech.

Supporters seek to minimize the importance of some of Bork's earlier writings, particularly a 1971 Indiana Law Review article setting out his controversial theory of constitutional law. "As a law professor, he often criticized the reasoning of Supreme Court opinions; that is what law professors do," the White House said in a briefing book on Bork.

However, the briefing book added, "Judge Bork understands that in the American legal system, which places a premium on the orderly development of law, the mere fact that one may disagree with a prior decision does not mean that that decision ought to be overruled."

But Bork's opponents point to his continued attacks on Supreme Court rulings since being named to the federal appeals court here in 1982.

NAACP Legal Defense Fund lawyer Eric Schnapper, who worked on the study released yesterday, said Bork has repeated his criticism of 12 of 21 groups of cases since becoming a judge and offered criticism of 10 other groups of cases.

Bork's statements on the importance of adhering to precedent offer ammunition for both sides.

"Certainly at the least, I would think an originalist judge would have no problem whatever in overruling a non-originalist precedent," Bork said in a 1985 interview with California Lawyer magazine. "It comes from nothing that the framers intended."

Asked in a 1985 interview with District Lawyer magazine whether he could "identify any Supreme Court doctrines that you regard as particularly worthy of reconsideration in the 1980s," Bork responded: "Yes, I can, but I won't."

Likewise, in his 1982 confirmation hearings, Bork said, "If a court became convinced that it had made a terrible mistake about a constitutional ruling in the past, I think ultimately the real meaning of the Constitution ought to prevail over a prior mistake by the court."

On the other hand, at the same hearings, Bork said: "The value of precedent and of certainty and of continuity in the law is so high that I think a judge ought not to overturn prior decisions unless he thinks it is absolutely clear that that prior decision was wrong and perhaps pernicious."

And in the District Lawyer interview, Bork said, "There are some constitutional decisions around which so many other institutions and people have built that they have become part of the structure of the nation. They ought not be overturned, even if they are thought to be wrong."

He gave as an example decisions extending the reach of the Commerce Clause, the foundation for the major civil rights legislation of the 1960s.

"Nothing from what Bork has stated indicates that he would be any more or less willing to overrule precedent than his brethren," Fein said. However, he said, "The ones he would be most willing to revisit are the right-to-privacy questions," including abortion.

Others disagree with that reading of Bork's position.

"My view of him from reading all that he has written or said in recent years is that he will be an aggressive judge in conforming the Constitution to his notions of what it should be, and that includes rejecting stare decisis where necessary," said Philip B. Kurland, a conservative law professor at the University of Chicago who is opposing Bork.