Kagan, 49, is not widely known for legal writings or for taking a stand on a controversial issue. And she has never argued a case in the federal courts. Yet, in her career in academia and in the Clinton White House, she has worked with nearly everyone who counts inside President Obama's legal circle, including then-professor Obama at the University of Chicago Law School.
Those who know her well say she has the intellect, insight and personality to succeed on the Supreme Court.
"She has an excellent chance, and she would be terrific," said Harvard Law School professor Laurence H. Tribe. "She has a masterful command of so many areas of law. And she's been vetted and recently confirmed. Her writing is not voluminous, which is also a plus."
And unlike nearly all the other potential nominees, Kagan is not likely to face sharp attacks from conservatives. At Harvard, she won glowing praise from prominent conservatives for bridging the ideological divide.
"Of all the good people Obama is considering, Elena is the really outstanding one," said Harvard's Charles Fried, who served as solicitor general for President Reagan. "It's clear where her heart is" -- she is no conservative -- "but she respects everyone and makes the conservatives feel comfortable," he added.
Meanwhile, a new name surfaced Wednesday on the short list of potential high court nominees: California Supreme Court Justice Carlos R. Moreno. A former federal judge in Los Angeles, Moreno was named to the high court by Gov. Gray Davis in 2001. He also served as a criminal court judge in Compton and a Superior Court judge in Los Angeles.
He is the only Democrat on the state Supreme Court and has had a moderate-to-liberal voting record. After the retirement announcement of Justice David H. Souter, Sen. Dianne Feinstein (D-Calif.) recommended Moreno, a Mexican American, and officials confirmed he is a candidate.
Besides Moreno, the others said to be under careful consideration are all women. They include Judges Diane Wood from Chicago and Sonia Sotomayor from New York, Michigan Gov. Jennifer M. Granholm and Homeland Security Secretary Janet Napolitano.
Kagan does not have the "real world" experience in politics of Granholm or Napolitano, a former Arizona governor. It is not clear whether she has the "quality of empathy" Obama has said he wants in a nominee. But she has had an uncanny knack for winning important admirers and avoiding enemies in a series of top legal jobs.
A native of New York City, she graduated from Princeton University and from the Harvard Law School where she, like Obama, was editor of the law review.
Moving to Washington, she was a law clerk for federal Judge Abner Mikva, later one of Obama's early political mentors in Chicago. Kagan was then a clerk at the Supreme Court for Justice Thurgood Marshall and worked briefly at the law firm of Williams & Connolly, whose partners included Greg Craig, now White House counsel.
In 1991, Kagan joined the law faculty at the University of Chicago, where she was an expert on administrative law and the 1st Amendment. She moved back to Washington as a White House lawyer in 1995, and later as President Clinton's deputy director of domestic policy.
Obama chose Kagan to be his administration's advocate before the Supreme Court, even though she had never argued there before. She passed up a chance to argue a case in late April. Her next opportunity will come in October -- if she has not ascended to the bench by then.
Obama on Wednesday met at the White House with key senators concerning the choice of Souter's successor, including Senate Majority Leader Harry Reid (D-Nev.) and Senate Minority Leader Mitch McConnell (R-Ky.). They largely talked about the timing of the nomination and the subsequent confirmation hearings.
Sen. Jeff Sessions of Alabama, the top Republican on the Judiciary Committee, said after the meeting that Republicans wanted 60 days between the time the nominee is announced and the start of hearings.
The White House's pick could come as early as next week. Under the GOP timetable, hearings would not begin until late July. That would risk the process carrying over into September, because of the Senate's August recess, something the White House and Senate Democrats are hoping to avoid.
Democratic aides stressed Wednesday that they would not be bound by Republican demands.