WASHINGTON (CNN) - Several influential organizations urged passage of health care legislation Wednesday in the face of growing liberal discontent with what many Democrats believe is now a watered down Senate bill.
Representatives of the AARP, Consumers Union and the Service Employees International Union, among others, pushed for quick Senate passage of Senate Majority Leader Harry Reid's sweeping $848 billion plan.
"Our organizations are here to say move the process forward," said Ron Pollack, head of the progressive group Families USA.
Reid's measure "has many important provisions that improve the availability and the quality of health care for Americans," said Consumers
Union's DeAnn Friedholm, which publishes the magazine Consumer Reports.
"We urge the Senate to move forward to keep working towards the many vital improvements not just in access, not just in cost, but also in quality and safety."
The new push came one day after former Vermont Gov. Howard Dean - a former presidential candidate and past head of the Democratic National Committee - ripped the Senate Democratic leadership's apparent decision to eliminate both a controversial government-run public health insurance option and a provision allowing 55- to 64-year-olds to buy into Medicare.
"This is essentially the collapse of health care reform in the United States Senate and honestly the best thing to do right now is kill the Senate
bill and go back to the House," Dean said in an interview with Vermont Public Radio posted on its Web site.
Liberal Democrats are increasingly angry with compromises that have been made in an effort to get the 60 votes needed to end Senate debate on the bill and proceed to a vote on final passage.
Unanimous Republican opposition to health care legislation so far means Senate Democrats need the backing of all 60 members of their caucus. Final Senate passage would require only a simple majority of 51 votes.
Most of the liberal anger has been focused on Connecticut Sen. Joe Lieberman. An independent who caucuses with the Democrats, Lieberman has been viewed as the main obstacle to the majority party's efforts to get the health care bill passed by the Senate before Christmas.
He threatened over the weekend to join a GOP filibuster if the bill contains either the public option or the Medicare expansion.
In an interview Tuesday with CNN, Lieberman said he was "moving very much in the direction of saying yes, pending just seeing what I've been told is happening with the bill."
Lieberman acknowledged he has angered some of his colleagues, but said he was acting on principle, not politics.
"I knew some of them were upset about positions I'd taken," Lieberman said. "But like each of them, I didn't get elected by telling my voters in
Connecticut that I would follow the majority of my caucus even if I thought on some things they were wrong. We each have to do what we think is right."
President Barack Obama met with Senate Democrats Tuesday and urged them to accept a compromise and pass the bill.
"The final bill won't include everything that everybody wants. No bill can do that," he said. "But what I told my former colleagues ... is that we
simply cannot allow differences over individual elements of this plan to prevent us from meeting our responsibility to solve a longstanding and urgent problem for the American people."
Obama insisted "any fair reading" of the Senate bill showed it meets the administration's criteria of lowering costs and expanding coverage while not adding to the federal deficit.
Democrats "may have to do what Mr. Lieberman wants" in order to pass the bill, Iowa Democratic Sen. Tom Harkin told CNN.
Lieberman supported letting older workers buy into Medicare in 2000, when he was the Democratic vice presidential candidate, and as recently as September in comments to a Connecticut newspaper. Now, he said both Monday and Tuesday, the country has huge deficits - as opposed to a budget surplus nine years ago - and Medicare is poised to run out of money in 2017.
The Medicare buy-in was part of a package of provisions announced by Senate Majority Leader Harry Reid last week as an alternative to a public option, which lacked enough support among Democrats to break a GOP filibuster. Negotiated by a team of 10 Democratic senators - five liberal and five moderate - the compromise package had been hailed by Reid, Obama and others as an important step forward in the health care debate.
The package also would allow private insurers to offer non-profit health coverage overseen by the government. But many senators have reserved judgment on the compromise proposal until the non-partisan Congressional Budget Office (CBO) provides its analysis of how much it costs.
The CBO estimate was expected to be completed as soon as Wednesday.
Another potential obstacle for Reid is moderate Democrat Ben Nelson of Nebraska, who said Sunday said he cannot support the Senate bill without tighter restrictions on federal funding for abortion. The Senate last week defeated an amendment proposed by Nelson and two other senators that would adopt tougher language on abortion funding contained in the House health care bill.
A compromise on the abortion language is possible, said Nelson, one of the 10 Senate Democrats who negotiated in private last week.
If the Senate eventually passes a health care bill, its version will have to be merged with the version the House of Representatives passed in November, which includes a public health insurance plan. The final bill would then need approval from both chambers before going to Obama to be signed into law.
Obama and Democratic leaders have said they want the bill completed this year. The Senate would need to finish its work this week to leave a realistic chance of meeting that schedule.
–CNN's Dana Bash contributed to this report