WASHINGTON — Senators began sparring Tuesday over Elena Kagan’s qualifications to be the next justice on the U.S. Supreme Court, but with her confirmation virtually assured, the debate largely served to highlight the rancorous divide between Democrats and Republicans in advance of this year’s congressional elections.

With a floor vote expected later this week, Kagan appears set to receive fewer yes votes than Justice Sonia Sotomayor a year ago. Kagan, 50, was nominated by President Obama in May to replace the retired John Paul Stevens on the high court.

As U.S. solicitor general, Kagan represents the government before the Supreme Court, but her career has largely been spent outside the courtroom.

She served as a lawyer and domestic policy adviser in the Clinton White House and for almost six years headed the faculty at Harvard Law School.

Since she was chosen, Republicans have cast Kagan as an inexperienced, progressive political operative who would work to preserve the president’s policy agenda once on the high court rather than serve as an objective jurist.

“She is young, but her philosophy is not,” said Jeff Sessions of Alabama, the top Republican on the Senate Judiciary Committee, warning that Kagan could serve on the court for more than 35 years. “It is old bankrupt judicial activism — a philosophy the American people correctly reject.”

Her supporters, on the other hand, painted Kagan as a brilliant legal mind and a fair-minded moderate who will build consensus at the court’s center.

Kagan “will do her best to consider every case impartially, modestly, with commitment to principle and in accordance with law,” said Democrat Patrick Leahy of Vermont, chairman of the Judiciary Committee.

But Leahy spent much of his time on the floor Tuesday decrying Republican threats to repeal the massive health care overhaul passed earlier this year should the GOP regain power in Congress, and arguing that the current Supreme Court under the leadership of Chief Justice John Roberts is committed to rolling back social progress.

“This radical conservative agenda is a threat,” Leahy said.

Republicans such as Sen. John Cornyn of Texas and Orrin Hatch of Utah shot back, saying that Kagan favors an unrestrained federal government and suggesting she would vote to deny a constitutional challenge to the new health care regime.

“In her hearing, Ms. Kagan refused to acknowledge any real limits on the federal government’s power,” Hatch said.

At least five Republicans, including Maine Sens. Olympia Snowe and Susan Collins, have indicated they will support her, enough to ward off a filibuster. One Democrat, Ben Nelson of Nebraska, has expressed his opposition, but in doing so, he said he, too, would not back any attempt to block the vote.

But Sen. George Voinovich, R-Ohio, dealt Democrats a blow when he said he’d oppose Kagan after voting for Sotomayor last year, citing her lack of judicial experience. “I have no idea what she’ll do on the bench,” he said.