"The time has come for universal health care in America," Obama said at a conference of Families USA, a health care advocacy group.
"I am absolutely determined that by the end of the first term of the next president, we should have universal health care in this country," the Illinois senator said.
Obama was previewing what is shaping up to be a theme of the 2008 Democratic primary. His chief rivals, Sen. Hillary Rodham Clinton and John Edwards, also are strong proponents of universal health care and have promised to offer their plans.
Obama said while plans are offered in every campaign season with "much fanfare and promise," they collapse under the weight of Washington politics, leaving citizens to struggle with the skyrocketing costs.
He said it's wrong that 46 million in this country are uninsured when the country spends more than any other nation else on health care. He said Americans pay $15 billion in taxes to help care for the uninsured.
"We can't afford another disappointing charade in 2008, 2009 and 2010," Obama said. "It's not only tiresome — it's wrong."
Obama's call was an echo of a speech he made last April when he said Democrats "need to cling to the core values that make us Democrats, the belief in universal health care, the belief in universal education, and then we should be agnostic in terms of how to achieve those values."
His argument Thursday not only will be considered through the prism of the presidential campaign, but weighed against Clinton's ill-fated plan to overhaul the health care insurance system when she was first lady. Even after leading that calamitous attempt in 1993, Clinton remains in favor of universal health care and has made it a central theme of her presidential bid.
"One of the goals that I will be presenting ... is health insurance for every child and universal health care for every American," she said at a community health clinic in New York on Sunday, the day after entering the 2008 Democratic field. "That's a very major part of my campaign and I want to hear people's ideas about how we can achieve that goal."
On Thursday, she criticized President Bush's proposal to make health care more affordable through tax breaks, arguing that it would lead to less funding for hospitals.
Addressing the U.S. Conference of Mayors, Clinton was self-deprecating in describing her own experience in the health care debate and joked that Mr. Bush would need some heavy-duty protection as he wades into the fight.
"I welcome his participation in the health care debate. I'm going to send him a suit of armor because I know anybody who puts a foot in the health care debate is gonna need that. I've got the scars and experience to show for it," said the New York senator.
Another candidate, Ohio Rep. Dennis Kucinich, also backs universal health care.