WASHINGTON -- President Barack Obama is expected to nominate Solicitor General Elena Kagan to replace retiring justice John Paul Stephens, positioning the Supreme Court to have three female justices for the first time in history.

Since Kagan is not a judge and has few legal opinions on record, critics may have a hard time finding reasons to oppose her nomination.

A Rare Thing in Modern Times

Kagan is that rarest thing in these modern times -- a non-judge nominated to the highest court. Much of her career has been in academia, like the years she spent as dean of Harvard Law School.

The president may be reasoning Kagan's thin resume will mean a relatively easy confirmation in the Senate, where she was confirmed just a year ago as his solicitor general.

She is seen as somewhat moderate and, in replacing the liberal Stevens, might actually make the high court more moderate.

Should Republican senators go along with such thinking, it could help avoid a battle on Capitol Hill this summer while lawmakers are in engaged in bitter election contests across the country.

"It's in the administration's interest and it's in Democrats up on Capital Hill's interest to make this a much smoother process," Republican strategist Kevin Madden said.

Kagan served as a White House adviser in former President Bill Clinton's administration. Then, as Harvard Law dean, she waged one of her few controversial public fights - opposing military recruiters on campus because she so dislikes the military's refusal to let homosexuals serve openly in the ranks.

A Vague Record

But she's supposedly so quiet about her opinions, few know where she stands on many judicial issues. Attorney General Eric Holder has speculated that will change during her confirmation.

"She's done a great job as solicitor general, the first woman to ever hold that job, the first woman to be the dean of the Harvard Law School," Holder told NBC's Meet the Press. "I think people ...will get an understanding of who she is, what her judicial philosophy is."

If she wins confirmation, the 50-year-old solicitor general would be the youngest justice on the bench, and the fourth woman ever to serve there.

She is also Jewish, meaning that when Stevens steps down this summer, it would be the first time ever that there's no Protestant on the high court.