WASHINGTON -- Six months into his historic presidency, Americans are beginning to show the first real signs of doubt that President Barack Obama can deliver on his promise of change.
A new poll out Monday suggested that amid the worst economic crisis since the Great Depression of the 1930s, rising unemployment, and a ballooning deficit, the honeymoon could be waning for Obama.
And the president's determination to push through a radical reform of the creaking US healthcare system could come to define the success or failure of his fledgling presidency.
Obama has invested much personally in his high-stakes campaign, a cornerstone of his 2008 White House race which saw him defeat Republican rival John McCain to become America's first African-American president.
But the far-reaching plans to afford health insurance for all Americans have left many worrying who will end up footing the bill.
Six months after his January 20 inauguration attracted record crowds and television audiences, Obama remains popular at home with a 59 percent approval rating according to a poll by ABC News television and the Washington Post.
But it was the first time that the rating had slipped below 60 percent. And it marks a six percent fall since June.
Obama's detractors meanwhile have plenty of fodder to fuel their discontent.
Unemployment has hit more than 10 percent in 15 states and in the capital Washington, the promised economic recovery has still not arrived and the nation's deficit has passed a trillion dollars.
While 52 percent of Americans said they still supported the Democratic leader's economic policies, that is down on 56 percent last month.
And 46 percent told the pollsters that they did not back Obama's proposals, with for the first time the numbers of people who strongly disapprove surpassing those who strongly approve.
Those voicing confidence in Obama's plans to kickstart the ailing economy have also tumbled from 72 percent before his inauguration to 56 percent today.
Despite frequent White House reassurances that "the green shoots" of economic recovery can be seen, many ordinary Americans are still hurting, rocked by job losses, a credit crunch and seemingly unending home foreclosures.
The Obama administration admitted Monday that it would delay releasing budget figures for a day, but denied it was to hide the true scale of the deficit.
Obama unveiled in February massive plans to restimulate the world's largest economy and create or save some three million jobs within two years.
He was met by a wave of skepticism notably among his Republican critics who have accused him of aggravating the deficit with his 787-billion dollar stimulus, burdening generations to come with a huge debt.
So more than anything it is likely to be the final cost which could scupper his plans to reform the healthcare system, one of the most expensive and least performing among the world's industrialized nations.
Former president Bill Clinton and his wife Hillary know too well the political cost of trying - and failing - to find a solution to the problem.
But Obama is determined to get his message across, and this week has a series of media and political events to publicize his case, including a primetime press conference on Wednesday evening.
He has fought back hard to keep his message on track.
"Just the other day, one Republican senator said - and I'm quoting him now - 'If we're able to stop Obama on this, it will be his Waterloo. It will break him,'" Obama said Monday.
"Think about that. This isn't about me. This isn't about politics. This is about a health care system that is breaking America's families, breaking America's businesses, and breaking America's economy."
Healthcare is just one issue on Obama's plate. He was also the driving force behind the stimulus plan, has ordered the closure of the Guantanamo Bay prison by January, and campaigned hard for legislation to limit greenhouse gases.
But healthcare reform looks set to be his biggest test yet, with many within his own Democratic party yet to be won over. With an eye on looming mid-term congressional elections in 2010, some fear they could pay the price at the ballot box.
Even among the president's supporters there is grumbling that his timetable, which would see a vote on an initial text by early August, is unrealistic.
"The Barack Obama experiment with America is a risk our country can't afford. It's too much, too fast, too soon," argued Republican Party chairman Michael Steele on Monday.
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