Key Democratic allies in the US health care battle warned Sunday that a Senate bill required major changes if it was to earn their support and give President Barack Obama a crucial victory on his top domestic priority.

Meanwhile, former Democratic National Committee Chairman Howard Dean told Huffington Post's Sam Stein that Democrats could be in "big trouble" because of delays in crafting health care legislation.

A knife-edge ballot Saturday saw Democrats scrape the 60 votes needed for debate to begin November 30, but wavering senators Joe Lieberman and Ben Nelson sent a strong message that they would not back the bill as it stands.

Lieberman, an independent senator from Connecticut who usually votes in line with the Democrats and did so on Saturday, opposes the creation of a government insurance program to compete with private firms, the so-called "public option."

"We have a healthcare system that has real troubles, but we have an economic system that is in real crisis," said Lieberman, who fears the government program would be too expensive for the cash-strapped US economy.

"I don?t want to fix the problems in our healthcare system in a way that creates more of an economic crisis," he told NBC's "Meet the Press".

On Monday, Huffington Post's Sam Stein reported, "One of the leading progressive champions of health care reform is pessimistic about the state of the debate in the Senate, saying he sees virtually no path to passing strong legislation and predicting potential congressional losses for Democrats as a consequence."

Stein adds,

Former DNC Chair Howard Dean told the Huffington Post on Monday that Senate Democratic leadership was "in deep trouble" on health care, even after Majority Leader Harry Reid cobbled together over the weekend the 60 votes needed to get legislation to the floor. The problem was as much about politics as policy.

"I think if you passed the Senate bill tomorrow it would be OK. But then the problem is they don't have any defense for their members in 2010," Dean said, noting that the public option would not become operational until 2014. "On the other hand, if they drop the public option [to placate moderate members], I think they lose seats."

"So this is really tough. I didn't anticipate being in this position. I thought it would pass. Maybe Harry has some magic up his sleeve. But I don't see how he gets those four votes [Sens. Joseph Lieberman (Conn.), Mary Landrieu (La.), Blanche Lincoln (Ark.) and Ben Nelson (Neb.)] without compromising the bill," Dean concluded.

The former Vermont governor warned that if the party allowed the four moderates to further water down the bill (or defeat it altogether) it could lead to primary challenges or a drop in fundraising from the party's base.

America's Thanksgiving holidays are set to be marked by bitter debate over the nitty-gritty of the bill, from its costs in terms of tax increases and fees to the merits or not of the "public option."

Divisive issues like abortion funding could also come to the fore while some Democrats may also seek funding for pet causes in their states in return for passing what amounts to the biggest shake-up of US health care in four decades.

The leading Democrat in the Senate, Harry Reid, faced three possible defectors in addition to Lieberman, any one of whom could have deprived him the 60 votes necessary to prevent Republican parliamentary delaying tactics.

Those senators -- Mary Landrieu of Louisiana, Blanche Lincoln of Arkansas, and Nelson of Nebraska -- have signaled a willingness to join Republicans if their proposed changes to core provisions of the bill are defeated.

Before eventually falling into party line on Saturday, Landrieu and Lincoln repeated their strong opposition to the "public option."

Nelson indicated on Sunday that he could be open to persuasion on the issue, although he prefers states to be able to opt in to program rather than having to opt out.

"We could negotiate a public option of some sort that I might look at, but I don't want a big government, Washington-run operation," he told ABC's "This Week" program.

Nelson has also demanded tougher restrictions on federal money subsidizing abortions, mirroring language the House of Representatives added to its version of the bill when it approved it in a 220-215 squeaker November 7.

The New York Times reported that the Obama administration was continuing to court two moderate Republican senators from Maine, Susan Collins and Olympia Snowe, in the hope of winning them over and breaking up the united Republican opposition on health care.

Debate in the Senate is expected to last at least three weeks, but Republicans hope to kill the bill or delay the battle into next year with the expectation that the 2010 midterm elections may make it harder for moderate Democrats to support it.

Senators voted 60-39 Saturday to formally start debate on legislation aimed at extending coverage to some 31 million Americans.

As well as the public insurance option, the Senate bill includes restrictions on dropping care for pre-existing ailments. It is estimated to cost 848 billion dollars through 2019 but cut the sky-high US budget deficit by 130 billion dollars over the same period.

A successful final vote -- expected a month away at the earliest -- would force the Senate and the House of Representatives to reconcile their rival versions of the bill and vote again on whether to send it to Obama.

The United States is the world's richest nation but the only industrialized democracy that does not provide health care coverage to all of its citizens, about 36 million of whom are uninsured.

Several US presidents since Theodore Roosevelt in the early 1900s have sought to overcome the traditional US suspicion of a wider government role in health care.

Washington spends more than double what Britain, France, and Germany do per person on health care, but lags behind other countries in life expectancy and infant mortality, according to the Organization for Economic Cooperation and Development (OECD).

(with afp report)