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U. S. President Barack Obama delivers his speech on healthcare reform to a joint session of Congress on Capitol Hill in Washington, Sepatember 9, 2009. REUTERS/Joshua Roberts (UNITED STATES)

President Barack Obama's media blitz on U.S. healthcare reform has prompted charges that he is risking overexposure, but the very public offensive could be a perfect prescription for his top domestic priority.

Since September 7, Obama has made a nationally televised address to a rare joint session of Congress and held rallies in Ohio, Minnesota and Maryland to promote his healthcare agenda, an issue that could be a defining one for his presidency.

His run of media interviews includes an unprecedented five that will air on morning TV talkshows on Sunday and he will court late-night viewers on Monday as the only guest on the Late Show with David Letterman on CBS.

The barrage has prompted charges that Obama -- derided by Republicans as the world's biggest celebrity as he ran for president last year -- is diluting his message, just as his fellow Democrats in Congress try to develop and pass a plan to overhaul the $2.5 trillion U.S. healthcare system.

But proponents say the White House made a mistake by leaving it to notoriously fractious Democrats in Congress to make the case for reform during the summer.

Meanwhile, the Republicans -- united -- told the public that healthcare reform would cost billions, cover illegal immigrants and fund abortions. Scare tactics included talk of death panels that would decide on care for the elderly and warnings of a descent into Soviet-style state control.

Analysts say Obama lost control of the message in the face of that opposition and insurance industry lobbying against plans for a government-run insurance plan -- the public option -- designed to bring more competition. Even many conservative Democrats worried about the program's cost.

In looking at the way the past four or five months of healthcare debate have gone, the White House needed to change their approach, said Dan Amundson, research director at George Mason University's Center for Media and Public Affairs in Washington.

Their best card is Obama himself and his ability to sway a crowd.

Obama is considered one of the most gifted communicators in recent Democratic Party history, with his campaign for the presidency praised as an almost perfect communications effort.

SENATOR OFFERED PLAN

Democratic Senator Max Baucus, chairman of the Senate Finance Committee, this week offered an $856 billion, 10-year plan to rein in healthcare costs and reshape the way Americans get coverage, which contains most of the proposals that Obama outlined in his speech to Congress.

Democrats spoke confidently about getting a bill through, although the Baucus measure has failed to gain the support of any Republican legislators.

Some Republicans say people are starting to tune out the president, contending that Obama is promoting an ill-advised plan that will cost far too much and be an unwarranted government intrusion into the private sector.

The more people learn about the president's plan, the less they like it, said Republican strategist Alex Conant.

That's not a problem the White House can solve simply by talking louder. The Democrats' healthcare overhaul is not unpopular because the president has not done enough Sunday shows. It's unpopular because the more people learn about it, the less they think it will improve quality while cutting costs.

With news available on the Internet, TV, radio and in print, the White House says it is merely responding to a diverse media market.

People are getting their news from so many different places and so many different outlets, that we're going to use the president to communicate through that fragmentation, White House spokesman Robert Gibbs said on Friday.

There's nothing that denotes that people are spending less time thinking about healthcare or watching the president.

Analysts said only time will tell whether Obama has overdone it.

The big trick for them will be to make sure the message and the points stay consistent without becoming sort of the canned speech, Amundson said.

But some early signs have been good.

Polls show Americans, who gave Obama a resounding victory in the election only 10 months ago, are responding.

A CBS poll after Obama's healthcare speech to Congress showed the highest approval ratings of the year on the issue, with 52 percent approving and 38 disapproving. His ratings were particularly high among Democrats, with 85 percent approving.

Viewership ratings for his speech were high, and a crowd of 15,000 people turned out in Maryland on Thursday for his campaign-style healthcare reform rally.

I think he needs to state his point of view more often, because there's so much negativity that it overshadows his main agenda, the reason why he wants to change healthcare, said Rachel Adams, 27, of Tempe, Arizona.

Morgan Garrett, 28, who was visiting Washington with Adams, said he did not find Obama's appearances overdone and that he supports reform, pointing to the basic issue that millions of Americans do not have any health insurance.

I think everyone should have healthcare, Garrett said.

(Editing by John O'Callaghan and Chris Wilson)