One New Hampshire friend of Souter’s told POLITICO that the justice made it clear last summer when he was home in between sessions that if Obama won he wanted to be the first to retire.
Never married, Souter is thought to miss the quiet life in the tight-knit Granite State after nearly 19 years on the court in Washington.
White House officials did not immediately respond to questions about Souter, 69. His possible retirement became the subject of intense interest Thursday when the Associated Press reported that Souter, unlike other justices, had not hired law clerks for the coming session.
Asked about the reports of Souter's retirement plans, Supreme Court spokeswoman Kathy Arberg said, "The justice has no comment." Souter also had no comment on the report about the clerks.
Souter hails from the court's relatively liberal branch, so his retirement is unlikely to represent a deep shift in the balance of power among the Supremes – and more a deepening and renewal of the left end of the bench.
But Obama would face competing imperatives in replacing him, including the pressure to appoint the first Hispanic to the Supreme Court and his own ties to prominent legal academics beginning with his years at Harvard Law School.
During his campaign for the White House, Obama suggested he'd take personal considerations into account in selecting judges.
"We need somebody who's got the heart, the empathy, to recognize what it's like to be a young teenage mom. The empathy to understand what it's like to be poor, or African-American, or gay, or disabled, or old. And that's the criteria by which I'm going to be selecting my judges," he told a Planned Parenthood conference in 2007.
The top candidate, on paper, is Judge Sonia Sotomayor, 54, a Clinton appointee to the Second Circuit Court of Appeals. She meets the empathy criteria, having grown up poor in the South Bronx, as well as Obama's preference for sterling credentials, having graduated from Yale Law School.
One question facing Obama is whether he would feel pressure to add another woman to the bench with the lone remaining female justice, Ruth Bader Ginsburg. Former Justice Sandra Day O’Connor, a Republican, has expressed disappointment that President George W. Bush did not replace her with a woman.
Others possible contenders for Obama include:
—Kathleen Sullivan, 53, is a professor and former dean at Stanford Law School. A Constitutional law expert, she has argued several cases before the Supreme Court and formerly taught at Harvard Law. Considered a liberal.
—Harold Koh, 54, is a former dean at Yale Law School. He is currently Obama’s nominee to be the chief legal adviser at the State Department, but his nomination has encountered heavy opposition from Republicans. Also considered a liberal pick.
—Elena Kagan, 49, is currently serving as Obama’s Solicitor General and was formerly dean of Harvard Law School. She served as deputy domestic policy adviser in President Clinton’s White House. Clinton nominated her to the D.C. Circuit in 1999 but she never got a hearing. Considered liberal, but perhaps not as liberal as others. Made a point to reach out to conservatives while at Harvard.
—Cass Sunstein, 54, an Obama friend from the University of Chicago Law School and Obama’s nominee to run the White House Office of Information and Regulatory Affairs. He once clerked for Supreme Court Justice Thurgood Marshall.
—Diane Wood, 58, is a judge on the Chicago-based U.S. Court of Appeals for the Seventh Circuit. She worked in the Justice Department under both Presidents Ronald Reagan and Bill Clinton. Wood was also an associate dean at University of Chicago Law School. Considered a moderate.
—Ann Willims, 59, also sits on the U.S. Court of Appeals for the Seventh Circuit. An African-American woman, she could be tough for Republicans to oppose because she was first appointed as a federal district court judge in 1985 by Reagan. Clinton elevated her to the appeals court. Considered a moderate.
NPR reported that Souter plans to retire to his native New Hampshire and has informed the White House of his decision. The Supreme Court will issue rulings and opinions until June.
Last month, a senior administration official involved in the nomination process signaled that the life experience of potential nominees would figure heavily in Obama's decisions about whom to propose for the highest court.
"The same principles apply in terms of looking for people with the highest professional competence and personal and professional excellence. We're looking for diversity again, not only just in gender and ethnicity, but also in experience in the law and in life," said the official, who asked not to be named. "The president has made clear that he's looking for judges, and I think this is true for justices, who have the ability or the experience to understand the plight of real people who are in the courts."
Souter's retirement has been the source of much speculation in his native New Hampshire. Many friends and associates in the small political and legal community there have believed his return home to be imminent.
A Harvard graduate and Rhodes Scholar, Souter served in private practice in Concord before serving as both state attorney general and as a state and federal judge. He was a little known figure in national legal circles before then-Senator Warren Rudman and Chief of Staff John Sununu urged President George H.W. Bush to appoint him to replace William J. Brennan.
Though closely aligned with New Hampshire's Republican establishment and initially feared by some Senate Democrats, Souter became a reliable vote on the court's liberal bloc. He has repeatedly voted to uphold abortion rights, drawing scorn from conservatives and becoming emblematic of what partisans on both sides see as the risk of appointing a largely unknown figure to the high court.
When the second President Bush sought to fill his first Supreme Court vacancy, "No More Souters' became a rallying cry on the right.
Jonathan Martin and Ben Smith contributed to this report.