Republicans and other critics of health care overhaul have seized on the poll numbers reflecting public opposition and unease to accuse President Obama and congressional Democratic leaders of trying to ram through a measure that Americans don’t want.

But the poll headlines don’t tell the whole story of how public opinion is being shaped and what effect the public mood will have on the prospects for passage of a health care bill and on next year’s midterm elections, opinion experts say.

Pollsters such as Scott Keeter of the Pew Research Center say it’s not surprising that public opinion has taken a negative turn. “When you have unified and vehement criticism of the legislation from one side, and division and heated debate among the other side, it’s no wonder that much of the public is ambivalent or downright negative about it,” he said. “I see little prospect that this will change unless and until supporters of reform agree on a bill and then promote it enthusiastically to the country.”

Drew Altman, president of the Kaiser Family Foundation, has studied public opinion surveys of previous overhaul efforts and sees a pattern. “Since time immemorial we’ve seen in these health reform debates that when they get really contentious and hot, people just get nervous and cautious about change and a little more comfortable with the status quo,” he said. “We’re seeing that again now.” (KHN is part of the foundation.)

There has been a common theme in the polls released in the last few weeks: Americans care far more about the economy and jobs than they do about health care reform; they are getting more worried about the costs to the country; they believe it will raise the deficit and their taxes; that they think if the legislation is passed it will hurt or make no difference to the quality of their own care or coverage, and they are concerned about government getting too deeply into the management of the system.

In the last two weeks, polls by the Washington Post/ABC News, Wall Street Journal/NBC News, the Pew Research Center, USA Today/Gallup, CNN/Opinion Research, and Quinnipiac University have shown pluralities or majorities of Americans opposing the health care reform legislation.

And the belief that, if legislation passes, Americans’ own health care costs would rise and quality of care would not improve was reflected in George Washington University Battleground and Kaiser Family Foundation polls, as well as in many of the other surveys.

The Kaiser poll, in particular, found that while 54 percent believed that economic problems in the U.S. make it even more important to tackle health care overhaul, that number was down from 58 percent from last month; the number of those who said the country can’t afford to act now rose from 36 percent to 41 percent.

But the polls can also put the wrong emphasis on findings and send the wrong messages about the state of play. As the public follows the debate and as the news media reports on each new poll, there is a tendency (noted by Mark Blumenthal of Pollster.com) to look at ups and downs of the legislation as there were a presidential horse-race in which the public has a direct vote. The final outcome, of course, will be determined by the votes of lawmakers whose constituencies may hold views different from what is reflected in national polls.

Sometimes there is a gap between what advocates on either side, politicians and the news media highlight, and what the public really cares about.

“The media got swept up in public option debate because that was where the activists and the Washington political battle were, while people were worried about things like costs and mandates and how it would affect them,” said Robert Blendon, professor of health policy and political analysis at the Harvard School of Public Health and director of the Harvard Opinion Research Program.

Nevertheless, Blendon said, “The polls carried by the media have a more significant impact on what members of Congress think because it has an impact on writers. It sets the tone for journalism coverage of an issue.”

That’s why Blendon cautions against reading too much into polls showing Americans placing the importance of the economy on jobs over health care by margins approaching or exceeding two-to-one. He concedes health care is a distant number two, but given how many major issues the media can digest at one time, it is still high enough on the agenda to get the attention it needs.

There is no question that the contentious debate in Washington is taking its toll on public opinion. While Keeter of the Pew Research Center says, “Our polling throughout the year has shown that the public supports most of the key provisions in the draft legislation,” that dynamic will change if the debate is drawn out too long. It’s no surprise, then, that President Obama and Senate Majority Leader Harry Reid, D-Nev., have pushed so hard to get the Senate bill done by Christmas.

But if the trend of public opinion raises the question about whether Obama and Democratic leaders have been wise to keep the health overhaul battle front and center, it is also true that they are aware of another consistent finding of these polls – which is that Democrats by big majorities want them to deliver on health care reform.

“Politics in America are extremely polarized,” said Blendon. “People who are elected in office pay a lot of attention to their own core group. I believe the Democratic leadership believes their core group wants this bill passed. I think for many of them this issue is really important to Democratic voters. And if they don’t do it, they fail their core base.”

While pundits and pollsters agree that the economy and jobs likely will be the most important dynamic in the 2010 midterm elections if there is not improvement, Blendon said that the failure of the Democratic leadership to show it can deliver on health care can have political consequences next year.

“I believe one of the reasons the House turned over in ’94 (to the Republicans) was that (President Bill) Clinton had fired the country up on health care and they saw him failing in it. That has the effect of depressing the turnout –union workers, liberals, your people who are active.”

Pew’s Keeter also said that, putting aside the economy, “the costs of failure on reform will probably be higher than costs of success, at least in terms of the public’s image of the Democratic Party’s ability to govern. But there could be a downside to success, largely because attacks on the legislation will not end when and if it passes” since many provisions of the bill do not take effect until well after next year’s elections.

Former Democratic National Committee chairman Howard Dean underscored this on Sunday when he appeared on Meet the Press. Given the complexity of the legislation, he said, “Republicans will make it a target and we’ll have a hard time explaining it” because some provisions don’t go into effect until 2014.