"President Obama is in the rare position of having a great deal of freedom in his choice and the types of people he considers," says Christopher Eisgruber, Princeton University provost and author of the 2007 book The Next Justice: Repairing the Supreme Court Appointments Process. "He has a very strong majority in the Senate. He has enormous popularity. ... Like most people, I would be very surprised if it is not a woman," Eisgruber says, adding he hopes Obama departs from the model of picking a lower court judge. "Diversity of experience is very important."
When Obama announced Friday that Souter would retire this summer, the president said he wanted someone with "that quality of empathy, of understanding and identifying with people's hopes and struggles."
As he brings his own priorities to the task, Obama can tap four basic models from the recent past: the demographic diversity candidate, the tried-and-true judge, the politician and the compromise candidate.
The diversity candidate
A selection that increases the court's demographic diversity could give new voice to a group that has been absent or underrepresented there. It also could build a president's support among a political constituency.
In 1967, when President Johnson chose Thurgood Marshall — a civil rights advocate who successfully argued against "separate but equal" school segregation — to be the first African American on the court, Johnson said it was "the right thing to do, the right time to do it, the right man and the right place." Fourteen years later, in 1981, Ronald Reagan fulfilled a campaign promise and chose the first female justice, O'Connor.
Ginsburg has said she wants another woman on the bench.
If Obama seeks a woman, it could help the chances of prominent female lawyers, including Elena Kagan, a former Harvard law school dean whom Obama tapped as the first female U.S. solicitor general, the government's top lawyer before the court.
Another choice in academia could be Stanford University law professor Kathleen Sullivan.
Some other prestigious female lawyers would bring added ethnic or racial diversity to the court. Among them: Sonia Sotomayor, a judge on the U.S. Court of Appeals for the 2nd Circuit, of Puerto Rican descent; Leah Ward Sears, chief justice of the Georgia Supreme Court, who is black; and Teresa Wynn Roseborough, chief litigation counsel for MetLife, who also is black. Roseborough, a former deputy assistant attorney general, has connections in Washington, including to Attorney General Eric Holder.
Among prominent male lawyers who would broaden the court's diversity are Harold Hongju Koh, dean of Yale University's law school, a Korean American whom Obama has nominated to be legal adviser to the State Department; and Massachusetts Gov. Deval Patrick, an African American who was assistant attorney general for civil rights under President Clinton and is a longtime friend of Obama's.
The tried-and-true judge
Tapping a lower court judge provides a president and his vetting staff with a record that could show how a nominee might vote as a justice. This is not a foolproof method: Justice Harry Blackmun, a Nixon appointee, increasingly voted with liberal justices over his 24-year tenure.
Another possible advantage of a judicial veteran is that she or he likely would be at ease discussing the law in nationally televised Senate Judiciary Committee hearings and, once on the bench, quickly would adjust to the demands of the high court.