Potter Stewart, a pragmatic, non-ideological Supreme Court justice whose mastery of internal politics made him a major force on the high court for 23 years until his retirement in 1981, died yesterday in New Hampshire following a stroke on Monday. He was 70 years old. Justice Stewart, saying he wanted to spend more time with his grandchildren, retired from the court at a relatively young age, 66, and his place was taken by Justice Sandra Day O’Connor.

Justice Stewart’s important contribution to the court and to the law, most observers believe, stemmed not from any major theories he propounded but from his consensus-building behind the scenes and his unwavering commitment to the objective consideration of each case, an approach in which he often said he took great pride.

Justice Potter Stewart (right) administers the oath of office to Robert Mardian as Asst. Attny. General in 1970. (Ken Feil/The Washington Post)

“I think it is the first duty of the justice to remove his own moral, philosophical, political and religious beliefs and not to think of himself as some great philosopher king and apply his own ideology,” Justice Stewart said in a 1981 news conference after announcing his retirement.

“A judge’s job,” he added, is to be “objective, conscientious, diligent and remember always that every person is equal before the law.”

Justice Stewart, a moderate Republican appointed by President Dwight D. Eisenhower in 1958, generally aligned himself with conservatives when he first joined the court. He dissented from many of the liberal rulings under Chief Justice Earl Warren, especially those extending federal court power to increase suspects’ rights.

He disagreed with the court’s famous Miranda ruling requiring police to warn suspects of their right to remain silent and to have a lawyer. And he dissented in Mapp v. Ohio, which said prosecutors in state courts could not use illegally obtained evidence in criminal trials.

But as the court under Chief Justice Warren E. Burger drifted to the right, Justice Stewart was perceived more as a moderate or liberal, especially on civil rights and social issues. He joined the court’s opinions striking down government aid to parochial schools as well as the court’s 1973 opinion legalizing abortion.

A former chairman of the Yale Daily News who was once inclined to a career in journalism, Justice Stewart may be remembered most as a strong defender of freedom of the press. But his views even there reflected the cautious, balanced jurisprudence that he espoused in other areas.

“So far as the Constitution goes,” Justice Stewart said in a 1974 speech, “the . . . press may publish what it knows and may seek to learn what it can.”

On the other hand, he said, the Constitution is “neither a Freedom of Information Act nor an Official Secrets Act.”

Consistent with those views, Justice Stewart joined the court’s 1971 ruling upholding the right of the press to publish the Pentagon Papers but wrote the majority opinion in a 1979 cases saying that the press was not entitled to access to closed pre-trial hearings.

Justice Stewart was known to those who frequented the court as an unusually accessible justice who, though blunt on occasion, would sometimes go to considerable lengths to make sure a reporter understood the fundamentals of some constitutional provision or court procedure. It was a role he appeared to enjoy and one he continued in a public-television series aired after his retirement. His post-retirement activity also included serving on federal appeals court panels and presidential commissions and reading books on tape for the blind.

Although Justice Stewart, when he resigned, said he wanted to leave the court “in good health,” his health began to deteriorate in 1982 after he broke several ribs and chipped his collarbone in a fall at his New Hampshire home.

Justice Stewart will be remembered for cutting to the heart of an issue in simple English in Supreme Court opinions.

In 1972, in a case striking down the death penalty because it was being imposed arbitrarily, Justice Stewart wrote: “These death sentences are cruel and unusual in the same way that being struck by lightning is cruel and unusual.”

Dissenting in a 1978 decision involving judicial immunity for a judge who approved the sterilization of a 15-year-old girl without her knowledge, he wrote: “A judge is not free, like a loose cannon, to inflict indiscriminate damage whenever he acts in his judicial capacity.”

Justice Stewart’s most famous quotation reflected the court’s difficulties in dealing with laws on obscenity. He admitted in a 1964 case that he might never succeed in defining the reach of “hard-core” pornography.

“But I know it when I see it, and the motion picture involved in this case is not that,” he said.

In his 1981 news conference, Justice Stewart had second thoughts about that quotation. “In a way I regret having said what I said about obscenity -- that’s going to be on my tombstone. When I remember all of the other solid words I’ve written,” he said, “I regret a little bit that if I’ll be remembered at all I’ll be remembered for that particular phrase.”

He said he wanted to be remembered simply as “a good lawyer who did his best.”

Justice Stewart, shy, somewhat patrician, was born to an established, well-to-do, Cincinnati family. His father was a Republican mayor there and was later on the Ohio supreme court. Justice Stewart, after attending a private East Coast preparatory school, Hotchkiss, and Yale University, returned to Cincinnati to practice law. He was a member of the city council and a vice mayor in the early 1950s.

He was the youngest federal judge in the country when President Dwight D. Eisenhower appointed him to the 6th U.S. Circuit Court of Appeals in 1954. Eisenhower gave Justice Stewart a recess appointment to the high court in October 1958 and formally nominated him for Senate confirmation in January 1959.

He had been considered a front-runner for chief justice in 1969 when Earl Warren retired, but he went to the White House to tell President Richard M. Nixon that he was not interested in the job.

Despite his inclination toward the center, Justice Stewart could bluntly and forcefully take a stand.

In 1967, in one of his most famous opinions, Katz v. U.S., which for the first time made government wiretapping subject to constitutional warrant requirements, Justice Stewart wrote that the Fourth Amendment “protects people, not things” and that a person making a telephone call from a phone booth is protected when he closes the door.

“What he sought to exclude when he entered the booth was not the intruding eye -- it was the uninvited ear,” he said, concluding that anyone who entered a telephone booth “and shut the door behind him, and pays the toll . . . is entitled to assume that the words he utters into the mouthpiece will not be broadcast to the world.”

Justice Stewart took another strong stand, this time alone in dissent, in the court’s landmark ruling striking down organized prayer in public schools. He said that opinion seemed to attract the most public reaction, generating 2,000 letters to his chamber.

In a later school-prayer case, Justice Stewart reflected the conservative states’ rights view: “It is not without irony that a constitutional provision on freedom of religion evidently designed to leave the states free to go their own way should now have become a restriction upon their autonomy.”

Justice Stewart’s pragmatism and moderation allowed him to join some liberal rulings and side with conservatives in other cases. Even though he dissented frequently during the Warren era, he joined, for example, the famous one-person, one-vote ruling, Baker v. Carr.

He also was seen as generally in favor of civil rights litigants, writing several important civil rights opinions, including one that said a Civil War law could be used to ban racial discrimination in housing.

But Justice Stewart dissented from a 1980 ruling that allowed government contracts to be “set aside” for minority business.

“There are those who think that we need a new Constitution,” Justice Stewart wrote in that case, “and their views may someday prevail. But under the Constitution we have, one practice in which government may never engage is the practice of racism -- not even ‘temporarily’ and not even as an ‘experiment.’ “

Asked 23 years ago about ideology, Justice Stewart said, “I have enough difficulty understanding what those words mean even in the field of political life. And I find it impossible to know what those words mean when carried over into the judicial work.”

The Cincinnati Enquirer’s editorial view when he came to the court 27 years ago proved accurate: “Judge Potter Stewart will assume a place on the United States Supreme Court Tuesday with the distinction of being regarded as both a ‘liberal’ and a ‘conservative’ depending upon who is doing the regarding.”

He is survived by his wife, Mary Ann, a daughter, Harriet Virkstis, and two sons, Potter and David.