A look at some possible candidates for the vacancy on the Supreme Court:
SAMUEL A. ALITO:
Dubbed "Scalito" or "Scalia-lite" by some lawyers because his judicial philosophy invites comparisons to Supreme Court Justice Antonin Scalia, Alito, 55, has been a strong conservative voice in his 15 years on the Philadelphia-based 3rd U.S. Circuit Court of Appeals, which is considered to be among the most liberal.
On one hot-button issue, Alito was a lone dissenter in a case striking down a Pennsylvania law requiring women seeking abortions to inform their husbandaw banning the possession of machine guns, Alito argued for greater state ruldn't be administrators."
A former Marine and Texas state judge, Garza, 58, sits on the New Orleans-based 5th U.S. Circuit Court of Appeals and was considered for a Supreme Court seat by the first President Bush.
Appointed a federal judge by President Reagan and elevated to the 5th Circuit in 1991, he has become best known for his views that Roe v. Wade should be overturned and that abortion regulation should be decided by state legislatures.
In 1992, for example, he voted to strike down a Louisiana law criminalizing abortion in deference to Supreme Court precedent. But in his opinion, Garza made clear his disdain for Roe v. Wade.
"Two essential facts seem apparent: The Constitution says absolutely nothing about abortion and ... the long-standing traditions of American society have permitted abortion to be legally proscribed," he wrote. "Because the decision to permit or proscribe abortion is a political choice, I would allow the people of the state of Louisiana to decide this issue for themselves."
In 1997, Garza voted with the majority to strike down a Louisiana law allowing judges to deny abortion to a minor and notify her parents. He criticized Roe's legal reasoning in a concurrence.
His opinions in those two cases have drawn the ire of women's and abortion rights groups, who fear that if elevated to the high court Garza would be a reliable vote to overturn Roe v. Wade.
An avid questioner in oral arguments, Garza's written opinions tend to be clear and scholarly.
In other cases:
—Garza dissented from a 5th Circuit decision in 2001 affirming a ucked Gonzales from a corporate law firm in Houston and named him the governor's general counsel. Since then, Gonzales' fortunes have risen in tandem with Bush's.
In 1997, Bush named Gonzales to the post of Texas secretary of state, making him the state's top elections official. Two years later, Bush nominated for a seat on the Texas Supreme Court.
After Bush became president in 2001, Gonzales left the court to become White House counsel, where he provided legal advice to the president and helped him fill vacancies on the federal bench.
It was in this position that Gonzales wrote a legal memo in 2002 contending that Bush had the right to waive anti-torture laws and international treaties that provide protections to prisoners of war. Critics have said the memo helped lead to abuses of the type seen at the Abu Ghraib prison in Iraq.
Gonzales also drafted rules for the military war tribunals created after terrorist attacks.
Soft-spoken and known as "the judge" to his White House colleagues or "Al" to friends, Gonzales also has critics on the right, who think he is too much of a moderate. The mistrust stems from his time on the Texas Supreme Court when he joined with the majority to affirm a pregnant teenager's right to seek an abortion without telling her parents.
Gonzales accused two dissenters in that case of "unconscionable judicial activism" — words that came back to haunt him after Bush nominated one of the judges, Priscilla R. Owen, to a seat on the federal appeals court. Democrats threw Gonzales' words back at the White House.
If nominated to the high court, Gonzales' advice to Bush regarding the treatment of prisoners in the war on terror is certain to be a source of questioning during Senate confirmation hearings, as was the case during hearings on his nomination to be attorney general.
Gonzales, 49, has an up-from-the-bootstraps story that President Bush is fond of telling. He is the son of Pablo and Maria, migrant farm workers from Mexico, neither of whom finished elementary school, and he grew up near Houston in a two-bedroom house with his parents and seven siblings.
Gonzales graduated from high school in the 1970s and, with little thought of going on to college, he joined the Air Force. He also spent two years at the Air Force Academy before he changed his mind and decided to pursue a legal career instead of his dream of becoming a pilot.
He graduated from Rice University and Harvard Law School before launching his career.
Critics of Gonzales' qualifications for a seat on the Supreme Court would highlight his limited judicial experience — two years on the high court in Texas. But the thin paper trail gives opponents scant insight into his judicial philosophy and thinking on major issues of the day to use against him.
Critics also may question his close relationship with Bush and whether that might jeopardize his independence or influence his court rulings.
During an online chat the White House sponsored earlier this year, Gonzales' answer to a question about his new job suggested an awareness of his changed role within the administration.
"While I was counsel to the president, I served as the president's lawyer. As attorney general, my primary allegiance is now to the Constitution and the American people," he replied.
Described as not being ambitious, Gonzales told senators at his confirmation hearing in January: "Let me make clear. I'm not a candidate for the Supreme Court."
EDITH HOLLAN JONES:
President Bush's father considered Edith Hollan Jones for a vacancy on the Supreme Court in 1990 but instead nominated David H. Souter. The announcement of Sandra Day O'Connor's retirement raises the possibility teir own policies — a hallmark of Chief Justice William H. Rehnquist's jurisprudence.
Criminal cases and rendering justice are more than theoretical exercises for Luttig, whose father was murdered in a carjacking more than a decade ago.
In 1994, Napoleon Beazley, 17, confronted businessman John Luttig in the driveway of his Tyler, Texas, home and shot him twice in the head. Luttig's wife, Bobbie, was shot at and crawled beneath the couple's Mercedes Benz and played dead.
In an interview with the Tyler Morning Telegraph, the younger Luttig said his father was a compassionate man who would have given his car to Beazley. He also testified at Beazley's trial, saying, "My dad was my hero. He still is my hero. I worshipped the ground he walked on. I still do."
Beazley was executed in 2002 after the Supreme Court deadlocked 3-3 on his appeal to stop the execution. A tie allows an execution to proceed.
Three justices recused themselves from the case — Antonin Scalia, Clarence Thomas and David Souter.
The younger Luttig had clerked for Scalia from 1982-83 when Scalia was a member of the U.S. Court of Appeals for the District of Columbia Circuit. In 1991, during the rancorous Supreme Court nomination fight over Thomas, Luttig helped shepherd the nominee through the process.
The Supreme Court is familiar territory for Luttig.
He served as a law clerk to Chief Justice Warren Burger from 1983-84 and a special assistant to the chief justice from 1984-85. After four years in private practice, Luttig worked in the Justice Department in the first Bush administration and was assistant o religious social service programs.
The self-described theologically conservative Christian, however, opposed government-sponsored prayer in schools.
McConnell, 50, also is a strong supporter of judicial restraint, arguing that Congress and not the courts should be the authority on defining and enforcing civil rights.
McConnell is not without critics from the political right. Lawyer Andy Schlafly, the son of longtime conservative activist Phyllis Schlafly, recently wrote that McConnell is "every bit as hostile to conservative legal principles as (David) Souter turned out to be." Souter was named to the Supreme Court by the first President Bush and has disappointed conservatives by repeatedly siding with its more liberal members. Schlafly cited McConnell's refusal to say Roe v. Wade should be overturned, as well as a legal philosophy that "hostile to government expressions of faith."
JOHN G. ROBERTS:
Roberts, who has been on the U.S. Court of Appeals for the District of Columbia Circuit since June 2003, was one of President Bush's least contentious picks for the bench.
A former Rehnquist clerk, Roberts was associate counsel to President Reagan from 1982-86 and then served in the first Bush administration, arguing cases before the Supreme Court from 1989-93.
During the Clinton administration, Roberts became a highly sought-after private lawyer in Supreme Court cases, representing clients such as the National Collegiate Athletic Association in a discrimination case, and carmaker Toyota in winning limits on a disabled workers claims.
Roberts had been in line to join the appeals court in 1992, but his nomination during the first Bush administration died in a Democratic-controlled Senate.
Roberts, 50, has generally avoided weighing in on disputed social issues. Abortion rights groups, however, have maintained that he tried during his days as a lawyer in the first Bush administration to overturn Roe v. Wade.
Roberts did help write a brief that stated "we continue to believe that Roe was wrongly decided and should be overruled." Pressed during his 2003 confirmation hearing for his own views on the matter, Roberts said: "Roe v. Wade is the settled law of the land. ... There's nothing in my personal views that would prevent me from fully and faithfully applying that precedent."
Roberts' nomination to the appellate bench attracted support from both ends of the ideological spectrum.
Some 146 members of the D.C. Bar signed a letter urging his confirmation, including officials from the Clinton administration. The letter stated: "He is one of the very best and most highly respected appellate lawyers in the nation, with a deserved reputation as a brilliant writer and oral advocate. He is also a wonderful professional colleague both because of his enormous skills and because of his unquestioned integrity and fair-mindedness.
A native of Buffalo, N.Y., Roberts received his undergraduate and law degrees from Harvard.
J. HARVIE WILKINSON III:
Wilkinson, 60, another prospect from the 4th Circuit, has been consistently conservative in his rulings since being put on the court by President Reagan in 1984.
For example, he was part of a panel that ruled in 2003 that the government could indefinitely detain without legal rights American citizens captured overseas in the war on terror. The Supreme Court reversed that decision, with moderate Justice Sandra Day O'Connor's blistering statement, "A state of war is not a blank check for the president when it comes to the rights of the nation's citizens."
The Supreme Court agreed with Wilkinson, however, in his 1987 ruling that struck down a city minority set-aside program.