With Longevity on Court, Stevens's Center-Left Influence Has Grown

"Potter Stewart once remarked that he's really John Paul Jones -- 'I have not yet begun to write,' " said Hutchinson, who served as a law clerk for Justice Byron R. White during Stevens's first term.

In 1989, Stevens dissented from the court's 5 to 4 ruling that recognized a First Amendment right to burn the American flag.

Yet his roots were in the liberal-to-moderate Midwestern wing of the Republican Party. As the country, the court and the GOP moved right, Stevens did not. He began to take a more favorable view of affirmative action, dissented from the court's pro-states'-rights movement -- and opposed the 5 to 4 decision favoring Bush in the disputed 2000 presidential election.

"He may have been moved to the left in the sense that he really rejects the direction of his party," said John O. McGinnis, a law professor at Northwestern University. "And who are the representatives of that on the court? Justices Scalia and Thomas. And in reaction, he moved a little to the left."

In a 2005 speech at Fordham Law School in New York City, Stevens alluded to his evolution, noting that "learning on the job is essential to judging."

Statistics compiled by the Washington law firm Goldstein & Howe show that Stevens is one of the court's most frequent dissenters. In the 2004-2005 term, he dissented 21 times -- more than any other justice.

But Stevens has won his share of close cases. In 2003, he and O'Connor co-wrote an opinion for the court upholding the McCain-Feingold campaign finance law's limits on political advertising and contributions by a vote of 5 to 4.

In 2005, after years of condemning the death penalty for offenders younger than 18, which the court upheld in 1989, Stevens won a fifth vote for his side.

He assigned the majority opinion to the swing voter, Anthony M. Kennedy, a moderate conservative who had previously supported the death penalty for juveniles. In a concurring opinion, Stevens defended Kennedy from a blistering dissent by Scalia.

This was three years after Stevens had written the majority opinion in a 6 to 3 decision that banned the death penalty for the mentally retarded.

Stevens also wrote the opinion for a 6 to 3 majority in a 2004 case in which the court rejected the Bush administration's view that prisoners at Guantanamo Bay should have no opportunity to dispute their detentions in federal court.

All of these cases showed that Stevens well understood the court's internal dynamics, according to which the liberals needed the vote of at least one of the court's centrists, Kennedy and O'Connor, to form a majority.

"He has become good at figuring out how much he can get out of them without losing them," Hutchinson said.

Forging majorities could become trickier for Stevens now that O'Connor has retired. If, as expected, the court's newest members, Alito and Chief Justice John G. Roberts Jr., prove to be consistent conservatives, only Kennedy will be left as a potential ally for Stevens and the three other liberal justices, David H. Souter, Ruth Bader Ginsburg and Stephen G. Breyer.

Stevens was also the author of what may have been the court's least popular decision in recent years, a 5 to 4 ruling in 2005 in which it upheld the right of local governments to make property owners sell out in favor of private developers.

Stevens's opinion argued that the result was dictated by precedent, and he made it clear that legislatures were still free to limit such property condemnations. Yet it was a major defeat for the conservative property rights movement, which portrayed the ruling as a blow to small businesses and homeowners. The backlash against the case was wide and fierce.

The Constitution's guarantee of life tenure for federal judges has been a double-edged sword, aiding judicial independence but also enabling some ailing, elderly justices to linger well past their prime. Still, only Holmes and Taney served at an older age than Stevens. Holmes was two months shy of his 91st birthday when he stepped down in 1932; Taney was serving as chief justice when he died in 1864 at age 87.

Today, Stevens is 85 years and 307 days old, 40 days older than the fourth-oldest justice, Harry A. Blackmun, was when he retired in 1994. At oral arguments, Stevens exhibits a full command of each case, politely prefacing his frequent questions to lawyers with "May I ask just one thing?"

According to family members and former law clerks, Stevens still writes the first draft of his opinions. He uses the Internet, studied French before a recent vacation in Europe and has become hooked on Sudoku number puzzles. An amateur Shakespeare scholar, he has publicly argued that the Bard's plays may have been written by Edward De Vere, the 17th Earl of Oxford.

Stevens has survived prostate cancer. He had a single-bypass heart operation in the 1970s -- which Susan Mullen described as "a real wake-up call." Since then, he has followed a low-fat diet, eating only a grapefruit for lunch.

He plays singles tennis three mornings a week. "From what I hear, he still gets to a lot of balls" on the tennis court, said Michael Gottlieb, a former law clerk with whom Stevens practiced for Wrigley Field.

Stevens has lived long enough to meet seven great-grandchildren. But he is not the oldest living member of his family. His brother William, 88, practices law part time in Naples, Fla.

"He is in excellent health," William Stevens said of his younger brother -- before excusing himself to return to his office.

William Stevens will turn 89 on April 19, one day before Justice Stevens turns 86.