President Obama and congressional Democrats face an uphill climb to reclaim the support of independent voters who vaulted them to the White House and huge majorities in Congress in 2008.
At the end of the bitter, intensely partisan battle to pass Mr. Obama's health care overhaul plan, independent voters, once captivated by hopeful campaign promises, are feeling burned and appear eager to oust Democrats in November's midterm elections.
"There is an overall sense of frustration that no one is listening," pollster Scott Rasmussen said about a problem that has plagued the political party in power for decades.
Mr. Rasmussen said the more pressing issue for Democrats is that swing voters are not just anxious about health care; they're also angry about the stimulus package and auto industry bailouts.
"It is gathering steam in the sense that the longer the frustration goes unanswered, the more it grows," said the founder and president of Rasmussen Reports.
In 2008, Mr. Obama's hope and change messages seemed to win over independents, and he captured about 52 percent of the independent vote in the election that year.
Self-identified independents continued to back Mr. Obama through June, with about 60 percent saying they approved of his job performance. But as the year wore on and the health care battle gained steam, their approval of the president plummeted and hardened in the low 40s, according to Quinnipiac University polls.
The president's approval ratings have not rebounded since the health care vote, but the latest Quinnipiac poll shows some positive movement for Mr. Obama. The percentage of independents who disapprove of Mr. Obama's job performance has dropped nine points, from 53 percent to 44 percent.
"It may be that passage of health care eventually helps President Barack Obama's approval ratings, but at this point there's no sign of that," said Peter A. Brown, assistant director of the Quinnipiac University Polling Institute.
"The White House believes that now that the legislation has been signed into law they can sell it to the American people. Approval of health care reform is growing - or disapproval is shrinking - but the president still has his work cut out for him."
Independents make for fickle voters. Two former political strategists for Bill Clinton said they've already seen independents begin to recoil from Republicans.
In February, Republicans held a 22-percentage-point advantage over Democrats among independents, according to the strategists' polling, but that had slid to just five percentage points by last month. The drop was attributed almost entirely to female independents, who went from favoring the GOP to favoring Democrats.
The strategists, James Carville and Stan Greenberg, who had front-row seats for Republicans' congressional victories in 1994 when Mr. Clinton was president, said they don't see a repeat this November - mainly because the GOP's high point has come and gone. That apex was in January, when Republican Scott Brown won the seat of the late Sen. Edward M. Kennedy.
"When we look back on this, we're going to say Massachusetts is when 1994 happened," Mr. Greenberg said.
In state after state, unaffiliated voters now hold the key to elections. Mr. Brown capitalized on that momentum in Massachusetts by telling voters he would be an independent voice in the Senate.
Seeking to boost the numbers, Mr. Obama is traveling across the country to trumpet the short-term benefits of the new health care law.
On Thursday, he was in Portland, Maine, where he predicted voters will start to support health care reform, and ridiculed early polls suggesting that voters continue to be unimpressed with the changes.
"It's been a week, folks," Mr. Obama said. "Before we find out if people like health care reform, we should wait to see what happens when we actually put it into place. Just a thought."
For now, the health care debate's political effect on Republicans and Democrats is easy to spot: Both sides are more energized.
A CNN poll released Tuesday found that 56 percent of Republicans said they're extremely or very enthusiastic about voting in November, a six-point jump since January, while 36 percent of Democrats said they're similarly enthused, which marks a five-point increase.
That enthusiasm gap bodes well for Republicans heading into the elections, but Mr. Greenberg and Mr. Carville said the GOP's brand image is likely too tarnished for them to retake the House and Senate.
They said in 1994, Republicans emerged from every policy fight with a strengthened image, but this year the GOP is suffering from each policy fight.
Mr. Carville predicted that Republicans will net about 25 House seats and six or seven Senate seats - not enough to give them control of either chamber, but enough to drop Democrats' margins dramatically.
He said, though, that this will be the third election in a row in which a party has scored those big congressional wins, after Democrats' double-dip successes of 2006 and 2008, and said voters are profoundly unhappy.
• Stephen Dinan contributed to this report.