Obama Interviews Solicitor General Elena Kagan for Supreme Court

President Obama on Friday interviewed Solicitor General Elena Kagan for an upcoming vacancy on the Supreme Court, a source close to the president's selection process told Fox News.

The interview came one day after Obama conducted his first known formal interview with federal appeals court Judge Sidney Thomas of Montana.

The White House has not confirmed either interview.

Kagan, who was interviewed last year for the seat now occupied by Justice Sonia Sotomayor, is considered a front-runner for this opening, along with federal appeals court judges Diane Wood and Merrick Garland.

Kagan is not considered to be highly controversial. She has an academic background -- as the dean of Harvard Law School, she was well-regarded for her performance and for reaching out to conservatives. She has a thin paper trail on past positions, but that's because she has never been a judge.

Obama is choosing a nominee to replace Justice John Paul Stevens, who is retiring this summer and he is expected to choose a nominee within a couple of weeks.

Obama's pick is not expected to upend the court's balance of power -- four on the left, four on the right, one in the middle. Stevens, the retiring justice, is the leader of the court's liberals.

Obama spokesman Robert Gibbs said earlier this week that Obama would be talking to candidates this week, but the White House has declined to characterize those conversations.

The president has been considering about 10 people as potential nominees.

Among the others are federal appeals court judge Ann Williams, former Georgia Chief Justice Leah Ward Sears, Michigan Gov. Jennifer Granholm, Homeland Security Secretary Janet Napolitano and Harvard Law School Dean Martha Minow.

Fox News' Major Garrett and The Associated Press contributed to this report.