“I just want to say we’ve just had a dramatic vote on the floor of the Senate,” Hutchison said afterward. “I have to say, though, that I don’t think this was the Senate’s finest hour,” criticizing Democrats for heavy-handed tactics in ramming the bill through the chamber.

Soon after Hutchison’s vote, her Texas Republican counterpart, Sen. John Cornyn (Texas), flipped his vote, prompting more cheers and smiles from the Democratic side of the aisle. Cornyn had lost an endorsement from the Texas Medical Association and had been the subject of heavy criticism and attack ads from the American Medical Association for voting to block the bill last month. The group said that Cornyn and Republicans were putting insurance providers before doctors who would need to limit access to Medicare beneficiaries if they received a 10.6 percent cut to their reimbursement rate from the government.

But with his Texas counterpart voting yes and the bill appearing likely to clear, Cornyn was boxed in a corner.

“I made a commitment all along that the cuts would not go through,” Cornyn said after his vote for the bill. “I still think the legislation is flawed and the idea of doing this every six months or 18 months is a terrible way to do business... I would hope the majority would consider legislation that would permanently resolve this. But it reversed the cut, and that’s the commitment I made to the physicians of my state.”

One Senate Republican moved almost immediately to ask Bush not to veto the measure and others can be sure to follow. Sen. Pat Roberts (R-Kan.), who supported the measure in earlier votes, issued a statement directed at the White House. “With a strong bipartisan vote, which has a veto-proof majority, I now urge President Bush to sign this bill immediately so that our seniors can continue to get the care that they need and deserve,” Roberts said.

Other Republicans who switched their votes were Sens. Arlen Specter (Pa.), Johnny Isakson (Ga.), Saxby Chambliss (Ga.), Mel Martinez (Fla.), Lamar Alexander (Tenn.), John Warner (Va.) and Bob Corker (Tenn.).

 “Were it not for Ted Kennedy, we would not be here today,” said Baucus, author of the Medicare bill.

“Ted wanted to be here today. He wanted to be here to do the right thing and stand up for seniors,” Baucus said.

Democrats credited Kennedy not just with casting the decisive 60th vote but also with breaking down the resistance of fence-sitting Republicans who jumped aboard when the fate of the vote was sealed.

“They knew the die had been cast and they gave up,” Reid said.

Reid defied President Bush’s threat to veto the bill and all but dared him to send it back to Congress for another vote. “Let the president veto it. We’ll override it,” Reid said. Reid also pointed to Bush’s reversal on the GI Bill as evidence that the president would back off a veto threat in the face of broad support in Congress.

McCain, who had largely stayed silent on the issue but opposed the bill,released a statement after the vote saying he supports the funding aspect of the bill needed to ensure quality care for seniors, though chastised the “partisan positioning over the well being of millions of our seniors.”

“We should not hold our doctors and seniors hostage to political gamesmanship and political votes,” he said in the statement. “While this bill does meet our obligation to provide proper reimbursements to Medicare physicians, it also rolls back important reforms, increases drug premiums, and places 2.3 million seniors at risk of losing the private healthcare coverage of their choice.”

J.Taylor Rushing contributed to this article.