WASHINGTON (Reuters) - President Barack Obama insisted he can overhaul the U.S. healthcare system without raising taxes for anyone but the wealthiest Americans, in a media barrage on Sunday as he sought to take control of the debate on his top domestic policy priority.

President Barack Obama speaks at the AFL-CIO Convention at the David L. Lawrence Convention Center in Pittsburgh, September 15, 2009. REUTERS/Larry Downing

In interviews with five Sunday television talk shows taped on Friday, he said his goals to expand healthcare and rein in costs would not lead to middle-class tax increases, and that he and his fellow Democrats are determined to pass the legislation despite a lack of Republican support.

After months of rancorous public debate, this week will be crucial in the effort to get what could be the defining issue for his presidency -- healthcare overhaul -- through Congress, where Democrats are the majority party.

The Senate Finance Committee meets starting on Tuesday to vote on and possibly amend a bill from its Democratic chairman, Max Baucus, which contains many of the elements Obama outlined in a major address to Congress on September 9.

A Gallup poll last week found that by 60 percent to 38 percent, Americans do not believe the government can expand healthcare coverage without raising taxes on the middle class or affecting the quality of care.

The $2.5 trillion U.S. healthcare system is the world’s most expensive -- it represents about a sixth of the economy -- but lags those of other advanced industrial states in quality of care.

The Kaiser Family Foundation study found insurance coverage for an average family costs $13,375 a year and premiums have increased 138 percent over the past decade. Forty-six million people in the United States lack any health insurance, leaving them at risk of economic catastrophe if they get sick.

Obama said on CBS’ “Face the Nation” he could still keep a campaign pledge not to raise taxes on those making less than $250,000. He said much of the cost of the overhaul could be funded by eliminating waste and abuse.

“I can still keep that promise because as I’ve said, about two-thirds of what we’ve proposed would be from money that’s already in the healthcare system but just being spent badly. And as I said before, this is not me making wild assertions,” Obama said.

‘BIG GOVERNMENT PLAN’

Republicans acknowledge problems with healthcare, but call the Democrats’ approach an unnecessary government intrusion in the private sector that would raise taxes for individuals and small businesses and cut benefits to the elderly.

“There is no debate in Washington, or around the country, about the need for us to fix our health care system. It doesn’t work well for everyone ... and it costs too much,” House Republican leader John Boehner said on NBC’s “Meet the Press.”

“But we can fix our current system, we can make it work better, we don’t have to throw it away and have this big government plan.”

The Baucus proposal would impose a fee on expensive health insurance policies. The fee could raise $215 billion over 10 years to cover a fourth of the $856 billion plan. It does not include a “public option” government-run insurance plan, which many Congressional liberals want but has been heatedly opposed by Republicans and insurance industry lobbyists.

Obama’s healthcare campaign has prompted angry demonstrations by Americans skeptical of the plan. Republican Representative Joe Wilson shouted “You lie” at Obama during his recent speech to a joint session of the U.S. Congress.

The exchange led former President Jimmy Carter to say Obama was a victim of racism, a claim Obama, the first black U.S. president, dismissed.

“You know, I think that it really has more to do with the fact that there are some people who think government can’t do anything. As I said, there’s some people who just cynically want to defeat me politically, but there’s nothing new about that,” Obama told Univision.

The media blitz, after repeated healthcare rallies and his major address to Congress on September 9, prompted criticisms that Obama risks diluting his message through overexposure.

“He’s been on everything but the food channel,” Republican Senator Lindsey Graham said on “Meet the Press.”

The White House says the president must make his case in a variety of ways because Americans get news in so many places.

Many analysts agreed, saying the White House erred earlier by leaving it to Democrats in Congress to formulate a strategy and sell it to the public.

“The White House needs to provide that single focal point, that single voice,” said Daniel Amundson, research director at George Mason University’s Center for Media and Public Affairs in Washington.

“It looks to me like the strategy is on the one hand, regain the rhetorical high ground, and on the other hand, cool off the language,” he said.