* Kagan is relative moderate
* May face questions over gays in military
* Has never been a judge (Adds confirmation, quote)
WASHINGTON, May 9 (Reuters) - President Barack Obama will nominate Solicitor General Elena Kagan on Monday for the U.S. Supreme Court, sources familiar with the matter said.
“It’s Kagan,” a Democratic official said when asked about the choice, first reported by NBC News.
If confirmed by the Senate, Kagan, 50, would fill the seat being vacated by liberal Justice John Paul Stevens.
Kagan is known as a relative moderate, but may still face questions from Republican senators on gays in the military.
Kagan’s appointment will buck a four-decade trend if she is confirmed because all justices in recent decades have been judges.
Kagan has served as a White House adviser during Bill Clinton’s presidency and a Harvard Law School dean but never as a judge.
If confirmed, Kagan would be only the fourth woman ever to be a Supreme Court justice.
Her nomination is unlikely to cause a damaging fight in the Senate before congressional elections in November or distract the Obama administration from other issues like jobs, financial regulation and climate change leglislation.
But Kagan could still have to deal with vigorous questioning by Republicans during her Senate confirmation on hot-button issues like her opposition to on-campus military recruiting at Harvard because of U.S. policy barring gays from serving openly in the military.
Obama appointed Kagan last year as the first female solicitor general, representing the U.S. government before the Supreme Court. Her initial Supreme Court argument in September was her first in any court.
Obama he wants his choice approved before the start of the high court’s upcoming term in October.
The retirement of Stevens, 90, who has been on the court for nearly 35 years, takes effect at the end of the current term in late June.
Democrats control 59 of the 100 Senate seats. A simple majority is needed for confirmation.
Kagan would not be expected to change the court’s basic ideological balance. Like Stevens, she would probably side in most cases with the three other liberal justices on the court, which is controlled by a five-member conservative majority.
She would join Ruth Bader Ginsburg and Sonia Sotomayor, who Obama appointed last year, as the court’s female justices.
The last two justices who had not been judges, William Rehnquist and Lewis Powell, joined the Supreme Court in 1972. (Additional reporting by Jim Vicini and Thomas Ferraro; Editing by Peter Cooney)
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