WASHINGTON (Reuters) - U.S. President Barack Obama said on Wednesday a broad healthcare overhaul was critical to an economic recovery and promised to push a reform package through Congress this year despite growing doubts about the plan, even among fellow Democrats.

In remarks prepared for his opening statement at an evening news conference, Obama said the biggest driving force behind the federal deficit was skyrocketing healthcare costs.

“If we do not control these costs, we will not be able to control our deficit,” he said after another day when leaders in Congress struggled to find common ground on the cost and scope of a healthcare plan, Obama’s top legislative priority.

Hopes dimmed in Congress that lawmakers could meet Obama’s goal of passing early versions by the August summer recess, but Obama appealed to congressional leaders to help Americans facing higher insurance premiums or lacking insurance.

“They are looking to us for leadership, and we must not let them down,” he said.

The measure faces opposition from all sides, with a group of conservative Democrats questioning the cost and funding, liberal Democrats concerned it would not do enough and Republicans blasting the $1 trillion-plus price tag and seeing a chance to deal a stinging blow to Obama and Democrats.

“If they try to fix our healthcare system like they’ve tried to rescue our economy, I think we’re in really, really big trouble,” said House Republican Leader John Boehner.

Senate Finance Committee Chairman Max Baucus said panel members meeting behind closed doors to negotiate a bipartisan agreement were making progress, but Republican Senator Orrin Hatch dropped out of the talks and said he would not support the bill as it now stands.

“It’s going to take time, but we’ll get there,” Baucus said.

Obama had stepped up his involvement, meeting with rebellious House of Representatives Democrats at the White House on Tuesday and scheduling healthcare events throughout the week, topped by the nationally televised news conference at 8 p.m. EDT (0001 GMT) on Wednesday.

The overhaul is designed to create a government-run insurance program to compete with private insurers, expand coverage to most of the 46 million uninsured Americans and hold down soaring healthcare costs that are rising faster than inflation.

But the details have proven difficult for lawmakers to nail down, and a series of opinion polls show Obama’s approval rating dipping and his support on the healthcare issue falling to below 50 percent in a Washington Post poll.

House Speaker Nancy Pelosi said there were enough votes to pass the bill in the House, but she did not give a firm timetable for a vote. Boehner questioned her vote count.

Slideshow ( 4 images )

“I’m not quite sure she knows whether she has the votes or not,” he said.

‘LONG WAY TO GO’

The August deadline for passing versions in each chamber of Congress was endangered by the lengthy negotiations, and Republicans pushed hard for a delay. Obama wants the first versions of the bills passed before the monthlong break to keep opposition from building during the recess.

Slideshow ( 4 images )

Dick Durbin, the Senate’s second-ranking Democrat, said senators were unlikely to meet the deadline. “We’re going to take a little longer to get it right,” he told The Hill newspaper.

The House Energy and Commerce Committee canceled a planned drafting session for the second consecutive day on Wednesday in order to work with the fiscally conservative Democrats on the committee known as “Blue Dogs,” who could scuttle the bill.

“We are making progress. However, we have a long way to go,” said Representative Mike Ross, leader of the Blue Dogs.

The group planned another negotiating session in the evening, as Obama prepared for his news conference.

Another panel, the House Ways and Means Committee, met to discuss taxes and other issues in its version of the bill. Its plan to add a tax on the wealthy, to raise about $544 billion over 10 years, has come under fire.

“Everyone believes we are going to make the schedule in the House,” said the committee’s chairman, Charles Rangel.

Members of the Senate Finance Committee, meanwhile, spent the morning looking for more ways to save money in the Medicaid health program for the poor, said Senator Kent Conrad.

The more savings lawmakers can wring from existing health programs, the less new revenue they will need to raise.

“We’ve gone through a series of options on Medicaid to try to see if there couldn’t be additional savings,” Conrad said.

Senator Olympia Snowe, a crucial Republican swing vote, said the senators negotiating the committee’s package want to make sure the insurance coverage provided through a proposed exchange program would be affordable.

“If you have an individual mandate you have to make sure that affordable plans are available,” she said.

The proposed state insurance exchanges would operate as a clearinghouse where individuals without employer sponsored health insurance and small businesses, with up to 50 employees, could shop for medical coverage plans.