WASHINGTON (Reuters) - After a landmark win in the House of Representatives, President Barack Obama’s push for healthcare reform faces a difficult path in the Senate amid divisions in his own Democratic Party on how to proceed.

On a 220-215 vote, including the support of one Republican and opposition from 39 Democrats, the House backed a bill late on Saturday that would expand coverage to nearly all Americans and bar insurance practices such as refusing to cover people with pre-existing medical conditions.

The battle now shifts to the Senate, where work on Obama’s top domestic priority has been stalled for weeks as Democratic leader Harry Reid searches for an approach that can win the 60 votes he needs to overcome Republican procedural hurdles.

“Take this baton and bring this effort to the finish line,” Obama urged senators on Sunday in an appearance at the White House, saying passage of healthcare reform would represent “their finest moment in public service.”

Democrats have no margin for error -- they control exactly 60 seats in the 100-member Senate. Some moderate Democrats have rebelled at Reid’s plan to include a new government-run insurance program, known as the “public option,” in the bill.

Senator Joe Lieberman, an independent who caucuses with Democrats, renewed his promise on Sunday to help Republicans block a final vote if the bill contains the government-run insurance option backed by Senate liberals.

“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,” Lieberman said on “Fox News Sunday.”

Republicans and some moderate Democrats have balked at the House bill’s $1 trillion price tag, new taxes on the wealthy and what they call a heavy-handed government intrusion in the private sector.

The overhaul would lead to the biggest changes in the $2.5 trillion healthcare system -- which accounts for one-sixth of the U.S. economy -- since the 1965 creation of the Medicare government health insurance program for the elderly.

DIFFERENT APPROACHES

The House bill includes a different version of the public option than the Senate. Senate Democrats also may not adopt the House bill’s requirement that all but the smallest employers offer coverage to their workers and its new tax on the wealthiest Americans to pay for the reforms.

Eventually, the House and Senate would have to reconcile their differences and agree on one bill to be passed again and sent to Obama for his signature.

“The House bill is dead on arrival in the Senate,” Republican Senator Lindsey Graham said on CBS’s “Face the Nation,” calling it “a bill written by liberals for liberals.”

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The House bill would set up exchanges where people could choose to purchase private insurance or a government-run option bitterly opposed by the insurance industry. It also would offer subsidies to help low-income Americans buy insurance.

Congressional budget analysts say it would extend coverage to 36 million uninsured people living in the United States, covering about 96 percent of the population, and would reduce the budget deficit by about $100 billion over 10 years.

The House vote was a vital victory for Obama, who staked much of his political capital on the healthcare battle. A loss in the House could have ended the fight, impaired the rest of his legislative agenda and left Democrats vulnerable to big losses in next year’s congressional elections.

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Former Alaska Governor Sarah Palin, the Republican vice presidential candidate in 2008 and a leader of conservative grass-roots opposition to Obama’s agenda, promised retribution in those elections against healthcare reform advocates.

“It’s on to the Senate now. Our legislators can listen now, or they can hear us in 2010. It’s their choice,” Palin said on her Facebook page, promising: “We will make our voices heard.”

Reid has been awaiting cost estimates from the nonpartisan Congressional Budget Office before unveiling a Senate bill, and has indicated Obama’s goal of signing a bill by Christmas could slip to 2010.

Reid said he hoped to receive those cost estimates in the coming days, and that he planned to bring a final bill to the Senate floor for consideration “as soon as possible.