The bill passed by a 220-215 margin late Saturday after fractious debate. Thirty-nine Democrats voted against the measure. One Republican, Rep. Anh "Joseph" Cao of Louisiana, unexpectedly voted in favor.
In a Rose Garden appearance Sunday, Mr. Obama said he is "absolutely confident" a health-care bill also will pass through the Senate.
But its narrow passage in the House, where the Democrats have a large majority, underscores the difficulties ahead. Senate Democrats are struggling to agree on how to pay for the overhaul and whether to create a new public insurance plan to compete with private insurers, as the House did. Friction over how the bill treats abortion, which almost derailed the House vote, is likely to divide the Senate too.
"If the public option plan is in there, as a matter of conscience, I will not allow this bill to come to a final vote," Sen. Joe Lieberman (I., Conn.) said on Fox News Sunday.
With the passage of the House bill, Congress moved closer than ever to providing Americans with near-universal health insurance -- a goal that has eluded many presidents since the days of Theodore Roosevelt.
The measure spends $1.05 trillion over a decade to provide health insurance to an additional 36 million Americans and creates a new public insurance plan by 2013. It requires most Americans to carry insurance, creates a new exchange where they can shop for it and gives the lowest earners tax credits to help them pay for it.
The Senate bill that Majority Leader Harry Reid is assembling will look markedly different from the House bill. While he wants to include a public insurance plan, Sen. Reid plans to give states the option of not participating in it. Instead of paying for the bill with a tax on the wealthy, the Senate plans to include a measure to tax high-value insurance plans. Employers will face smaller penalties for not providing insurance.
Sen. Reid (D., Nev.) said he expects to get cost estimates for the Senate bill from the Congressional Budget Office in the next couple of days, and that he hopes to bring a bill to the Senate floor "as soon as possible." Democratic leaders had aimed to deliver a bill to the president this year, but that deadline could slip into 2010.
The Senate faces the added challenge of parliamentary rules that effectively require 60 votes for passage, rather than a simple majority in the House, and give individual senators enormous power to gum up the works.
Among the last-minute roadblocks for the House bill was a successful push by antiabortion Democrats to prevent the bill's new federally subsidized insurance coverage from including abortion. The U.S. Conference of Catholic Bishops, which brokered the deal, is already placing pressure on Senate Democrats to do the same in their bill. Sen. Reid is himself antiabortion and faces re-election in a conservative state.
"It's almost always easier to pass a bill in the House than in the Senate," said Sen. Charles Schumer (D., N.Y.). "So the difficulties in the House show how tough it's going to be for us. But like the House, we'll succeed, because every Democrat, from the most liberal to the most conservative, knows that failure is not an option."
House Speaker Nancy Pelosi was confronted Saturday night with the defection of numerous centrist Democrats from swing districts. They may have become more skittish due to the victories Tuesday of Republican gubernatorial candidates in Virginia and New Jersey.
The nearly 40 Democrats who voted against the legislation Saturday comprised a mix of party moderates, Southerners and freshman facing tough reelection fights. An analysis of the vote shows that 22 of the 39 Democrats who opposed the bill were members of the fiscally conservative Blue Dog Coalition, including three of the group's four leaders. These Democrats had expressed concern before the vote that the legislation called for too much federal spending.
The debate played out in an unusual Saturday session marked by emotional speeches and sharp rhetoric. Members of both parties carted their children and grandchildren to the speaking podium in a 14-hour showdown that was at turns theatrical and contentious.
Republicans described the bill as an unprecedented power grab that would raise -- not lower -- medical costs and further cripple the economy. They lambasted the legislation for creating new taxes and failing to curb frivolous medical-malpractice lawsuits.
"Does this bill mean the government will take over running health care? Yes," said Rep. Paul Ryan (R., Wis.). "But what's worse, this bill replaces the American idea with a European-style social-welfare state."
Mr. Obama came to the Capitol on Saturday morning and assured Democrats they would remember the vote as their finest moment in politics should he sign it into law.
His plea, part of a last-minute push by the White House, was critical in winning over wavering Democrats. But more important was a last-minute concession by Ms. Pelosi, bowing to pressure from the Catholic bishops, to bring an amendment to the floor that tightened insurance coverage for abortion. It passed in a 240-194 vote that flipped the usual voting lineup, with 176 Republicans joining 64 Democrats in favor. Democrats who favor abortion rights said they were devastated by the change but swallowed hard and voted in favor of the broader bill.
Democrats portrayed their bill as a moral imperative on par with Medicare and Social Security. They argued it would fix the worst aspects of the medical system by preventing insurers from denying coverage to the sick and protecting consumers from financial ruin caused by medical bills. The Congressional Budget Office estimates that by 2019, the House bill would leave about 96% of legal residents with health insurance, up from 83% now.
To pay for expanded coverage, the bill calls for hundreds of billions of dollars in cuts to Medicare aimed at eliminating what the bill's supporters describe as wasteful spending. It levies a 5.4% tax on individuals earning more than $500,000 a year and couples earning more than $1 million a year. All but the smallest employers would be required to provide insurance and pay for most of the premium, or they would face a fine of up to 8% of their payroll.