But gay rights groups — disappointed that Obama didn't pick an openly gay man or woman for his Cabinet — are pushing him to put the first openly gay justice on the Supreme Court.
Within hours of word of Souter's departure, the Gay and Lesbian Victory Fund was hailing the candidacy of a First Amendment scholar and former dean of Stanford Law School, Kathleen Sullivan. "Out lesbian a contender for Supreme Court," one of the group's web sites declared.
Another Stanford law professor on the "frequently mentioned" lists, Pam Karlan, has been open about being a lesbian, colleagues and former students say. In response to an e-mail from POLITICO, Karlan expressed no reticence about discussing her sexual orientation, though she downplayed talk about being a possible nominee.
"It's no secret at all that I'm counted among the LGBT crowd," she wrote, using a common acronym for the lesbian, gay, bisexual and transgendered community. As for the possibility she'd be nominated, Karlan said, "Given the landscape, I'm flattered, but not fooled, by having my name tossed around."
Gay and lesbian activists said they were excited that the two women are being publicly considered - and guardedly optimistic that one of them might be picked.
"I think the community was hopeful we would see the first openly gay or lesbian Cabinet secretary and that didn't happen, which was a little disappointing," Denis Dison of the Victory Fund said. "The same thing is happening now with the Supreme Court vacancy...It's not so much we want to check that box at the Supreme Court level, but that achievement would be breaking the glass ceiling in a huge way."
In March, Obama named an open lesbian, Emily Hewitt, to be the chief judge of the federal Court of Claims, but judges on that special court do not have lifetime tenure. He also nominated another lesbian, Maria Demeo, to serve as a D.C. Superior Court judge.
However, in response to questions from POLITICO in recent days, White House aides declined to say whether sexual orientation was among the diversity factors the president planned to consider either with respect to a Supreme Court nominee, or judicial nominees more generally.
During his brief statement to reporters on Friday, Obama said nothing at all about diversity being a factor in his decision.
When press secretary Robert Gibbs addressed the issue, he put the focus not on a nominee's demographic profile but his or her life experience. Gibbs spoke of "ensuring diversity in their background and experience" and said Obama "is looking for somebody more with a diversity of background of experience than anything else."
When pressed about whether race and gender were part of the diversity calculus, Gibbs said tentatively, "I think a diversity of experience would include some of that."
Some conservative activists say they doubt Obama will nominate a gay or lesbian Supreme Court justice because the nominee's sexuality could become a political distraction.
"I think that would be a bridge too far for him to be honest because that would enter a whole new element into the debate that I don't think he's ready for," Tony Perkins of the Family Research Council said. "A parallel to that would be Bill Clinton's gays in the military battle, which really hurt his agenda from that point forward."
Perkins said his group would not investigate anyone's sexual preferences and planned to focus on a nominee's judicial views. "The issue is the ideology," he said.
But attorney and veteran gay rights advocate Dixon Osburn said: "We can all look at the Supreme Court and see it eeds more gender diversity. It needs more racial diversity, it needs more sexual orientation diversity. It's hard to get everything in one pick, but all those things need to be considered part of the conversation."
Osburn said he expects that if Obama concludes that a gay or lesbian candidate is best for the Supreme Court job he will nominate the person and deal with any fallout. "I don't think he would shy away from that, but first and foremost he's going to pick someone he thinks has constitutional gravitas," Osburn said.
The underrepresentation of open gays and lesbians on the federal bench is evident. Advocacy groups say they know of none among appeals court judges and only one in the district courts, Deborah Batts, who was nominated by President Bill Clinton in 1994.
"While people of color and women continue to be underrepresented at all levels of the federal judiciary, 'out' LGBT judges are nearly invisible among their ranks," Kevin Cathcart of Lambda Legal wrote in a January letter urging Obama to appoint more gay and lesbian judges.
Historians say the Supreme Court has never had an openly gay or lesbian justice, or even a nominee.
Sullivan, too, has been open with students and colleagues about her sexuality. In 2006, at a legal seminar about the evolution of gay rights, Sullivan joked that lawyers should have argued homosexuality is actually a religion. “After all, gay men and lesbians have our rituals, our creeds, our incantations, and special ways of dressing,” she said. The former Stanford dean did not respond to an e-mail seeking comment for this article.
Both Stanford professors have been active for gay legal causes.
Sullivan co-wrote the brief for gay rights advocates in the 1986 Supreme Court case, Bowers v. Hardwick, challenging Georgia's anti-sodomy law. In a 5-4 ruling, the court found the law constitutional.
Karlan wrote a law professors' amicus brief in the 2003 case, Lawrence v. Texas, which overturned Bowers and ruled that laws against consensual sodomy were unconstitutional.
In 2007, Sullivan wrote an amicus brief on behalf of Karlan and other law professors, urging the California Supreme Court to legalize gay marriage, which the court did. Voters later reversed the decision.