Although Chief Justice William H. Rehnquist (search) will probably go down in history as one of the justices who sided with President Bush in the contested 2000 election, his true legacy may well reveal him to be a uniter on a deeply divided court.
"It's a strong competition between him and Earl Warren (search) for being the most successful chief justice," said Martin Belsky, professor at the University of Tulsa College of Law and author of "The Rehnquist Court: A Retrospective."
Though Rehnquist was known as a "great dissenter" before President Reagan nominated him for chief justice in 1986 — he found himself on the losing side of such high-profile cases as Roe v. Wade — the high court's leader was able to coax the justices into majorities, all the while retaining the respect of his ideological opposites.
"Rehnquist plays the good solid citizen. He has his positions, they're ideological, but he doesn't try to attack, he doesn't try to go full-bore on the history," Belsky said prior to the justice's death. "He basically is the straight shooter. He has very good relationships with the justices, and more importantly has been able to use [those relationships] in an effective way to develop pluralities of four, and more often than not, majorities of five ... he is often the conciliator."
Many court observers assumed the 80-year-old Rehnquist, who was battling thyroid cancer, would decide to step down while Republicans had a majority in Congress. But while he looked frail in recent months, he refused to retire and worked until two days before his death.
Moreover, he was not the oldest justice on the court; that title belongs to John Paul Stevens (search), 85, who has sat on the court since the Ford administration.
Rehnquist's death may have less impact on the court than the retirement of Justice Sandra Day O'Connor (search) earlier this year.
While O'Connor was frequently the swing vote on 5-4 opinions, Rehnquist almost always took the conservative position, a precedent both John Roberts (search), nominated by President Bush to replace O'Connor, and Rehnquist's replacement can be expected to follow.
No top Democrat on the Senate Judiciary Committee has threatened to filibuster a new nominee to the Supreme Court, but how the Democrats actually respond depends on factors other than the pick being Bush's.
Few doubt Bush's nominee to replace Rehnquist will be an anti-abortion conservative. The degree of conservatism appears to be key.
After a protracted fight over judicial nominees in the Senate, low approval ratings and strong resistance to some of his second-term domestic agenda items, the president may be reluctant to start a war with Democrats by nominating conservative lightning rods Antonin Scalia (search) or Clarence Thomas (search) to be chief justice.
In "A Court Divided: The Rehnquist Court and the Future of Constitutional Law," author Mark Tushnet wrote that over the course of Rehnquist's tenure, two camps of conservatives emerged: traditional, "country club" Republicans such as Sandra Day O'Connor (search) and Anthony Kennedy (search) and more modern Republicans driven by social issues like Scalia and Thomas.
Rehnquist was arguably of both camps, and Bush may be tempted to appoint a justice more in tune with Scalia and Thomas.
"It strikes me as an extreme provocation to nominate Scalia or Thomas to be the chief justice," Tushnet, a Georgetown law professor, told FOXNews.com.
Scalia, whose outspoken gruffness has earned him a cult following of sorts, has in recent months touched off speculation he is lobbying for the job by softening his rhetoric in lectures and talks.
While the 69-year-old may seem like the preferable choice by virtue of his age and ideology, outrage at his nomination would prevent him from getting a pass in Congress, Belsky said.
"Scalia is the logical person. He's younger, ... he was a justice like Rehnquist was before [being elevated to chief justice], but I think the outrage would be so strong. He would not be a great politician [among the justices]. He's been giving all these talks recently where he's been Mr. Nice Guy, but I think it's a little bit too late for that," Belsky said.
And Thomas, who is hotly opposed by Democrats, may be too much of a hassle to nominate in the administration's eyes.
Tushnet predicted the Bush administration would ultimately decide on a "solid, moderate Republican" in the mold of Rehnquist. Other court-watchers say it is likely the White House not only has its picks for Rehnquist's replacement already lined up, but they are probably candidates who are ideologically close to Bush. To do otherwise would risk alienating his religious conservative base.
Belsky suggested that the nominee to replace Rehnquist would be a conservative appeals court judge. Two names that several court-watchers have tossed up are Michael McConnell (search), a former law professor who sits on the 10th Circuit and J. Michael Luttig (search), who sits on 4th U.S. Circuit Court of Appeals.
Some observers say they believe Bush prefers someone who will actively reshape the court to line up with the president's ideals, something Rehnquist did not do.
Moreover, the pick need not be a judge: Rehnquist, who served as an assistant attorney general for President Nixon, is one in a long line of high-court justices who never wore the robe before his appointment to the bench.
"A surprise pick would be a politician who has some legal credibility who can really mold the court as a political leader," Belsky said, citing Attorney General Alberto Gonzales (search) as an example. "[Bush may want] a chief justice who would be able to mold the court as it changes over time and keep that majority which eventually Bush will have."
Former Solicitor General Ted Olson (search), who argued on Bush's behalf in 2000's Bush v. Gore and is a familiar presence at the court, has also been floated as a candidate. But nominating someone who has never sat on the bench can be risky.
"Presidents have been burned by appointees. [Former Justice] Lewis F. Powell Jr. (search) was the ABA [American Bar Association] president. He was a conservative. And then he ended up on the court being fairly liberal," Belsky said.
More recently, Justice David Souter (search), who as a Republican appeals court judge was appointed during President George H.W. Bush's term, also turned out to be a liberal on the court.
The recent battle over judicial filibusters may be just a taste of what lies ahead in Congress. The deal brokered by moderates from both parties managed to squelch tensions, but could ultimately tie Democrats' hands come nomination time.
For one thing, it's unclear what kind of nominee would meet the "extraordinary circumstances" clause of the agreement — comedian Bill Maher joked that the nominee would have to smell of sulfur.
Democrats will likely risk the obstructionist label if Bush's pick is considered to be as far to the right as appeals court appointees Janice Rogers Brown (search) and Priscilla Owen (search), who just won confirmation after years of delay.
"This is not about appointing the secretary of agriculture, who is going to be gone after George W. Bush is gone," said Democratic strategist Bob Beckel. "The Constitution and the Federalist Papers make it clear — this is a joint decision ... I can assure you if George Bush tries to nominate someone like Priscilla Owen, there's going to be a major fight and there should be."