WASHINGTON - The Senate confirmed U.S. Solicitor General Elena Kagan on Thursday as the 112th justice to the Supreme Court. She will be the fourth woman to sit on the court.

On a 63-37 vote, Kagan, who will succeed retired Justice John Paul Stevens, became the second justice President Obama has placed on the high court. One year ago, Sonia Sotomayor won confirmation as the court's first Latina.

Some Democrats have said they hope that the lifetime appointment of Kagan, a consensus-building liberal, will nudge the court slightly to the left.

However, she is unlikely to immediately alter the current closely divided ideological makeup of the court, which is often split 5 to 4 on major decisions. While expected to fit comfortably within the liberal wing of the court, she does not seem to be as liberal as Stevens was during his final years on the bench.

Along with her relative youth, Kagan, 50, brings a résumé unlike any of those with whom she will serve.

She will be the first appointee since 1972 to join the court with no judicial experience. A former law professor and dean of Harvard Law School, Kagan worked briefly for a law firm and argued her first case before an appellate court 11 months ago. It happened to be before the Supreme Court, the first of six cases she argued as the nation's first female solicitor general.

Five Senate Republicans supported Kagan: Maine Sens. Susan Collins and Olympia Snowe, South Carolina's Sen. Lindsey Graham, retiring Sen. Judd Gregg of New Hampshire and Indiana Sen. Richard Lugar.

One Democrat, Ben Nelson of Nebraska, opposed her.

Kagan watched the vote with her Justice Department colleagues in the solicitor general's conference room. Chief Justice John Roberts will swear her in at the court on Saturday.

Democrats hailed Kagan's legal acumen and suggested that her widely acknowledged charm might appeal to the critical swing vote of Justice Anthony Kennedy on the nine-member court. Of her career, Senate Majority Leader Harry Reid, D-Nev., said: "She has brought people together of every ideological stripe."

Republicans criticized Kagan's lack of judicial experience and questioned whether she would adhere to "the rule of law." Senate Minority Leader Mitch McConnell, R-Ky., called her "someone who has worked tirelessly to advance a political agenda."

One of three women

Kagan will join Sotomayor and Justice Ruth Bader Ginsburg in the first bloc of three women serving on the court at the same time.

Kagan's confirmation continues a period of remarkable change for the court; she is the fourth new justice in the past five years. She is replacing a 90-year-old legend who served longer than almost any other justice.

Because of her work as solicitor general, she has already identified about a dozen cases from which she will recuse herself, including the first case on the court's opening day of the term, Oct. 4, regarding laws related to mandatory minimum sentencing for convicted criminals.

Rivalry with Roberts

Kagan's lack of judicial experience probably will hamper her at first -- she has, after all, never written an opinion. But she has also been pointing toward this day since posing in judicial robes in a high school yearbook photo.

Kagan appears to have an easy rapport with her ideological opposite, Justice Antonin Scalia. She held a lavish dinner for him at Harvard, where he attended law school, and he responded to Republican criticism about her lack of judicial experience by defending her background.

More intriguing will be her relationship with Roberts, 55. The two youngest members of the court are likely to serve together for decades and already have a complicated past.

In the late 1990s, President Bill Clinton selected Kagan for a seat on the U.S. Court of Appeals for the District of Columbia Circuit, but the Republican-controlled Senate never brought her nomination for a vote. The job was filled by Roberts.

Roberts is tough on many of the advocates who argue before the court, but he has been particularly blunt with Kagan. Some court observers think they have a natural rivalry; others say their encounters receive more attention because she had been mentioned as a candidate for the high court.

Kagan avoided the sort of scrutiny that some nominees have faced, as much of political Washington focused on other issues such as the war in Afghanistan and the oil spill in the Gulf of Mexico. According to the Gallup polling group, support for Kagan's confirmation slipped from 46 to 44 percent after her confirmation hearings in late June. More than 20 percent of voters had no view of her, making her the least known Supreme Court nominee in nearly two decades.