The polls on health care legislation show waning support, but Democrats are betting that the only thing worse than passing a bill many of them don't like is not passing one at all.

No one has stated the health care calculus more bluntly, or faces the risks more starkly, than House Speaker Nancy Pelosi, who faces the possibility of double-digit election losses among House Democrats in November.

Failure to enact health care legislation, she said, "would be very bad for the American people and very, very bad for us."

The House and Senate have approved separate health care bills and lawmakers intend to reach a compromise version in the coming weeks for both chambers to vote on.

The retirements next January of two once-safe incumbent Senate Democrats, Connecticut's Christopher Dodd and North Dakota's Byron Dorgan, paradoxically may intensify Democrats' resolve. They are expected to lose their 60-vote, filibuster-proof margin in the Senate, but that means whatever controversial legislation they hope to enact has to be done this year.

Climate change and immigration may already be dead. That leaves health care as a last stand.

Democrats also say they are taking the long view, trying to achieve a social policy breakthrough on a par with the 1935 enactment of Social Security and striving toward their dream of universal coverage that dates back to the Truman presidency.

"A lot of Democrats have begrudgingly come to the conclusion that breaking the seal on health care and getting a real reform done, even if it is not the legislation that you would really have wanted, is still an eminently desirable goal," said Democratic consultant Chris Lehane.

Enthusiasm wanes

National polls consistently show widespread opposition. The Real Clear Politics poll average shows 50 percent of Americans are opposed to the bills and just 38 percent support them.

A year of Democratic in-fighting, compromises and relentless GOP attacks have deeply tarnished health reform's luster. Most people think it will raise their own premiums. A large majority - 78 percent in a Rasmussen poll - expect it will cost more than projected and many experts agree it falls short on cost control, the key problem in health care.

Even worse for Democrats, enthusiasm on the left has evaporated with the Senate defeat of the public option of a government-run plan. Many Democratic liberals are now deriding the bill as a sellout to insurance companies that would cover only half the uninsured.

Push to pass bill

California Sen. Barbara Boxer, facing a tough re-election fight against Republican challenger Carly Fiorina, is one of health reform's most avid supporters. Former President Bill Clinton personally warned Senate Democrats to pass health care legislation or face a re-run of 1994, when Democrats lost their 40-year-old House majority and their Senate majority after Clinton's health reform collapsed.

Clinton said failure this time would be "a colossal blunder."

Democratic leaders are racing to get final legislation to President Obama's desk by his State of the Union address in February, hoping to pivot immediately to the lack of "jobs, jobs, jobs," as Pelosi puts it, that is stirring such an ugly mood among voters.

Polls show that while Republicans, independents and liberal bloggers may hate the health care legislation, rank-and-file Democrats solidly support it.

Democrats "have an unhappy choice," said Larry Sabato, director of the Center for Politics at the University of Virginia. "If they don't pass the bill, they demoralize Democrats and remove much of the rationale for having Democrats in charge."

And because 2010 is a mid-term election year, when mainly only the party faithful turn out, "It's all about the bases," Sabato said. "If they demoralize their base, they're looking at another 1994."

Pelosi has acknowledged the public's lack of enthusiasm but said once a final bill is on the table it will be easier to "merchandise."

"We are in a define-or-be-defined occupation," she said, and until Democrats have united behind one piece of legislation, they have a hard time selling its benefits.

Democrats point to internal polling that shows stronger support for specific pieces of reform, such as a ban on insurance company denial of coverage to sick people and policy cancellations when people get sick.

Still, many of the promised benefits are far off into the future. Most legislation loads goodies up front and saves bad medicine for later. But to meet President Obama's demand that the legislation not "add one dime to the deficit," Democrats had to reverse that formula.

Partly because it takes time to implement such sweeping changes - and partly to achieve the appearance of deficit reduction over 10 years - the legislation raises some taxes right away and postpones several expensive items, such as subsidies for the uninsured, for as long as four years.

Cost control unknown

Whether the legislation controls costs in the long run is hard to predict. The Congressional Budget Office said the Senate bill might lower costs by a quarter percent of gross domestic product after 2019, but warned that is little more than a guess. Much depends on the success of obscure pilot programs and a new Medicare commission that would recommend savings.

Conservatives argue that even the new regulations on insurance companies will have the effect of increasing premiums for everyone else.

"All those are going to add to the cost of policies," said Grace Marie Arnett, president of the Galen Institute, a think tank on health care and tax reform. "The main thing they have been trying to fix - lowering costs - is going to get much worse in the short term."

Exchanges popular

One of the most popular items in the bills, the new insurance exchanges that allow some people to shop for plans, would not take effect until 2013 at the earliest.