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The lobbying on the measure, which was already intense, will only grow.

Already the American Medical Association, which praised Thursday’s vote, said the bill needs fixes to stop medical payment boards from meddling with doctors’ decisions, while the U.S. Chamber of Commerce, which opposed passage, said the upcoming negotiations between the House and Senate offer a chance to “start over.”

Republicans have been monolithic in opposing the measure, calling it a “historic mistake” and arguing it falls short on Mr. Obama’s principles of allowing people to keep their insurance if they like it, and of reducing the long-term portion of gross domestic product that goes to health care spending.

Sen. Olympia J. Snowe, the Maine Republican who had been courted by Mr. Obama as a potential supporter and who voted for a bill in committee, gripped the edges of her desk as she voted against the new version on the floor.

And with her votes earlier this week arguing that the measure is unconstitutional, she has probably sealed off any ability to sign onto a bill later no matter what the changes. Republicans point to polls that show a clear majority of voters oppose what Democrats are doing on health care — though Democrats say when they get a chance to explain themselves, those polls will turn around.

“I believe that the negativity that leader McConnell and others have continually displayed on the floor has peaked, and now, when people learn what’s actually in the bill and all the good it does, it’s going to become more and more popular,” said Sen. Charles E. Schumer, New York Democrat.

The Democrats who wrote the House’s version of health care legislation praised the Senate for acting, but those plaudits masked the difficulty of reconciling the two bills.

Sen. Ben Nelson, Nebraska Democrat, and Sen. Joe Lieberman, Connecticut independent, who are linchpins of the Senate deal, have said they cannot accept the public health option that liberal House Democrats have demanded be in the bill.

And Mr. Nelson and Rep. Bart Stupak, Minnesota Democrat, have insisted pro-life language preventing federal taxpayers’ money from going to pay for abortions be included in any final bill — something other Democrats in both chambers say they’ll try to lift.

An early morning motorcade delivered Vice President Joseph R. Biden Jr. to the Capitol to preside over the vote, which lasted a little more than 10 minutes — possibly the quickest roll call vote the Senate held all year. Mr. Reid had the goof of the day. When the clerk called his name he initially voted “No,” setting the entire chamber laughing. The embarrassed Democratic leader corrected himself, and the clerk pointedly repeated his “Aye” vote.