"The most important thing that has changed," said Stuart Taylor of the National Journal, "is the downward spiral of partisanship in judicial nominations. It's reached a point where either party is going to make a fight on almost anyone unless the candidate is displeasing to the base of the president's party."
The administration has worked from its early days at vetting and exploring potential candidates for the court.
Those efforts intensified when Justice David Souter announced his retirement in May 2009. At the time, President Obama said that he was looking for a candidate with the "quality of empathy, of understanding and identifying with people's hopes and struggles, as an essential ingredient for arriving as just decisions and outcomes."
Top candidates went through extensive vetting before Obama settled on Justice Sonia Sotomayor. The short list then included Judge Diane Wood, Elena Kagan, Homeland Security Secretary Janet Napolitano and Michigan Gov. Jennifer Granholm.
Elena Kagan, 49, currently serves as the president's solicitor general. She is known as one of the finest constitutional scholars in the country, dazzling both liberal and conservative friends with her intellectual prowess and her ability to find consensus among ideological opposites.
Judge Diane Wood
Judge Diane Wood, 59, of the U.S. Court of Appeals for the 7th Circuit, was nominated by President Clinton in 1995. She has a wide array of job experiences away from the bench, including positions in the U.S. government at the departments of State and Justice, and as a teacher at the University of Chicago. While at the university, she played a key role in developing policies on sexual harassment and maternity leave. Unlike Kagan, Wood has had to wrestle with hot-button issues such as abortion. Potential confirmation hearings would be lively and controversial.
Homeland Security Secretary Janet Napolitano, 52, enjoys a close relationship with the president and would be an "outside the judicial box" candidate, but may be roundly criticized for her comments after the arrest of Umar Farouk Abdulmuttalab, who attempted to bring down a Northwest Airlines flight with explosives. Napolitano initially told ABC News, "Once the incident occurred, the system worked." A day later, she had a slightly different message on NBC News: "Our system did not work in this instance," she said. President Obama later ordered an extensive review.
Other Possible Candidates
Others, such as Leah Ward Sears, former chief of the Georgia Supreme Court , are also on potential short lists, but those lists can shift.
"Short lists probably don't change too much from vacancy to vacancy, but rankings within the short list probably fluctuate based on who's being replaced, Kendall said.
he noted that, unlike the previous vacancy, the next one could be filled by a male.
Many believe that Obama could turn to Judge Merrick Garland, 58, a graduate of Harvard Law School and former law clerk for Supreme Court Justice William Brennan, Jr. He currently sits on the U.S. Court of Appeals for District of Columbia Circuit.
Another possibility is Cass Sunstein, 55, a close confident of the president who currently heads the White House Office of Information and Regulatory Affairs.