Despite polls showing growing public doubts about his healthcare overhaul, U.S. President Barack Obama vowed on Wednesday to get a reform bill through Congress this year even without Republicans on board.

David Hall, M.D., (L), examines Maria Pantoja at the El Franco Lee Health Center in Houston, Texas, July 28, 2009. REUTERS/Jessica Rinaldi

I promise you, we will pass reform by the end of this year because the American people need it, Obama said in Wakarusa, Indiana, where he traveled to tout his economic initiatives. We're going to have to make it happen.

Obama's drive for healthcare reform, his top legislative priority, has been attacked on all sides for its $1 trillion cost and scope. Democrats have feuded over how to pay for it, and Obama's popularity has slipped as the debate dragged on.

A Quinnipiac University poll released on Wednesday found 52 percent of voters disapprove of Obama's handling of healthcare while 39 percent approve. That was a shift from 46 percent approval against 42 percent disapproval in a July 1 survey.

Concerns about spending too much and adding to the deficit appeared to fuel the change, with 72 percent saying they do not believe Obama can overhaul healthcare without expanding the deficit.

No Republicans have backed the healthcare proposals under consideration in Congress, and months of Senate Finance Committee negotiations with three Republican senators have not produced a deal. Obama said time was about up.

I think at some point, sometime in September, we're just going to have to make an assessment, Obama told MSNBC after his appearance in Wakarusa, saying his priority was a plan that reined in healthcare costs, improved care and regulated insurance companies.

Obama wants to expand insurance coverage to most of the 46 million uninsured Americans and make it harder for insurance companies to prohibit coverage of those with pre-existing conditions.

I would prefer Republicans working with us on that because I think it's in the interest of everybody. That shouldn't be a partisan issue, he said.

'A DELAY GAME'

Democratic Senator John Rockefeller told reporters he suspects the three Republicans negotiating with Senate Finance Committee Chairman Max Baucus -- Charles Grassley, Mike Enzi and Olympia Snowe -- ultimately will reject a Democratic healthcare reform plan.

My own personal view is that those three Republicans won't be there to vote for it, not in committee when it comes right down to it, he said. So this will evolve into three or four months of a delay game, which is exactly what the Republicans want.

The Senate adjourns at the end of the week for a monthlong summer recess, joining the House of Representatives, which adjourned last week. Three House committees and one Senate committee have passed versions of the healthcare bill, while Senate Finance is still at work.

Baucus said other Democrats believed the party's negotiators on Senate Finance should keep working, be bipartisan, but sometime in September we are going to have to make a decision.

Advocates on both sides are preparing for a fierce public relations battle this month. Baucus and Senator Chris Dodd of the Health and Education Committee, the other panel to pass a healthcare bill, held a briefing for Democratic senators on Wednesday to get them acquainted with the proposals.

Obama sent a message to his grassroots supporters asking them to get involved during the August break, contacting their representatives and taking at least one action in support of healthcare reform.

The cost of inaction is simply too much for the people of this nation to bear, he said in the message.

The six Finance Committee members trying to reach a bipartisan deal -- three Democrats and three Republicans -- met again on Wednesday and discussed a proposal for an independent Medicare Commission to oversee the healthcare program for the elderly.

They were set to meet with Obama at the White House on Thursday to discuss the status of talks, a congressional aide said.

Baucus told reporters the panel would make judgments about Medicare payments while preserving an appropriate level of congressional involvement in setting reimbursement rates.

We're trying to strike the right balance and we did. I think we came up with a pretty good resolution, he said.