Sandra Day O'Connor's retirement from the U.S. Supreme Court on Friday took legal scholars by surprise and could mean another year on the bench for Chief Justice William Rehnquist.
"If she had retired in the next couple of years, that would not have been particularly surprising," said Michal Belknap, a legal historian and constitutional law professor at California Western School of Law. "That she did it right now, it's very surprising. Potentially it could have huge effects."
The first woman to serve on the nation's highest court, the 75-year-old O'Connor has been described as a moderate conservative and many times was the decisive vote in 5-4 rulings.
"She's probably turned out to be a more important justice than a lot of people would have anticipated."
O'Connor is the first Supreme Court justice to retire in 11 years, and her decision signals the beginning of what could be a contentious battle for her successor.
The court concluded its 2004-05 session Monday and won't reconvene until October.
"She was fairly conservative in some areas, like she was very strong on federalism and state's rights," said University of San Diego School of Law professor Michael Ramsey. "And she was moderate in some other areas, like abortion. She tried to stake out a middle ground. She was a complex person on the court."
Rehnquist, meanwhile, has been the source of retirement rumors for months. The chief justice, 80 and ailing with thyroid cancer, has offered no hint as to his future plans.
Ramsey, who once clerked for Justice Antonin Scalia, speculated that Rehnquist likely will preside over the court for at least one more year to ensure a smooth transition for the court's newest member.
"These things are very difficult to predict, but he likely would have already announced that he was going to retire," Ramsey said. "Also, it would be somewhat disruptive for the court to have two vacancies, but it has happened before."
Ramsey heard sources informally tell him Rehnquist's health appears to be improving.
The talk now focuses on President Bush's nominee and the confirmation process.
Belknap wonders if O'Connor is trying to influence the choice of her successor by making her announcement a month before Congress adjourns. A majority of the Senate needs to confirm any nominee Bush makes.
"I have a hunch that she may be trying to pressure him into picking somewhat of a moderate who would be relatively easily confirmed," Belknap said.
Ramsey doesn't think the president is likely to select a candidate too extreme or controversial. However, the nominee probably will be more conservative than O'Connor, he said.
"She was obviously a pivotal person on the court, and the person who replaces her becomes an important one," Ramsey said.
The Associated Press contributed to this story.