A little more than three months after Justice David H. Souter announced his intention to retire, the Senate on Thursday confirmed Sonia Sotomayor to become the Supreme Court’s first Hispanic justice. The vote was 68-31.

The outcome had been foretold for weeks, given the Democrats’ overwhelming margin in the Senate and Sotomayor’s competent but cautious performance during her four-day confirmation hearing before the Judiciary Committee in July.

Nine Republicans joined all Democrats present and two independents in voting for Sotomayor, who becomes the third woman to serve on the high court. She has served on the U.S. Circuit Court of Appeals for the 2nd Circuit since 1998.

Robert C. Byrd , D-W.Va., 91, who has been absent much of the year due to illness, arrived in the chamber in a wheelchair and left immediately after voting to confirm Sotomayor. Barbara A. Mikulski , D-Md., who broke her ankle last month and underwent surgery last week, also was wheeled into the chamber still wearing hospital bracelets on her wrist. But Edward M. Kennedy , D-Mass., who is being treated for a brain tumor, was not present.

Senators sat quietly through the roll call, rising to cast their votes as their names were called. The sole late arrival was Jim Bunning , R-Ky, who signaled his vote before reaching his desk. Standing in the back of the chamber was Rep. Jose E. Serrano , D-N.Y., who hugged Charles E. Schumer , D-N.Y. after the presiding officer, Al Franken , D-Minn., announced the outcome.

Schumer was greeted with applause and cheers from a group of civil rights activists gathered outside the chamber after the vote. “Good work, everybody,” Schumer said to the group. “What a day!”

After the confirmation vote, the Supreme Court announced that Chief Justice John G. Roberts Jr. will swear in Sotomayor on Saturday at the court. The court will hold a formal investiture ceremony on Sept. 8.

“This is a wonderful day for Judge Sotomayor and her family, but I also think it’s a wonderful day for America,” President Obama said after the vote had concluded.

A majority of the GOP caucus united against Sotomayor, a sign of difficulty to come for Obama’s future nominees should Democrats lose seats in the next year’s midterm elections or during a possible second term.

Given Republican resistance to Sotomayor, liberal activists say that Obama should not hesitate nominating a liberal should there be another Supreme Court vacancy.

But such a move could make it more difficult to hold on to the votes of moderate Democrats who lined up behind Sotomayor despite opposition from the National Rifle Association.

Leahy joked that some Republicans would have voted no even “if President Obama had nominated Moses the law giver.”

Sotomayor, 55, is not likely to change the ideological balance of the court; Souter was part of the four-member liberal bloc that includes Justices John Paul Stevens , Ruth Bader Ginsburg and Stephen G. Breyer .