Neither the Senate nor the House of Representatives is likely to meet Obama's challenge to vote before they leave for a month-long break in early August, erasing what he had hoped would be a momentum-fueling win.
Republicans who oppose Obama's approach are thrilled, saying Democrats finally see the wisdom in not rushing through what would be the first in-depth overhaul and expansion of the US health care system in decades.
"Getting health care reform right is more important than rushing through some slipshod plan and calling it reform," Senate Republican Minority Leader Mitch McConnell said Friday.
Other Republicans have candidly declared they hope to derail health care reform in order to hand Obama his first major political defeat, which one Republican said might be the president's "Waterloo."
And some Democrats fret privately that, come September, health care will compete with Senate action on historic climate change legislation, efforts to toughen financial system rules, and pass annual spending bills to fund the government for the fiscal year that starts October 1.
But to hear the White House and some experts and veterans of past legislative battles tell it, the plan is far from doomed.
"I just want people to keep on working, just keep working," Obama said during a visit to the electorally crucial battleground state of Ohio on Thursday. "I want to get it done by the end of this year."
"It's daunting but doable. And nothing focuses congressional activity like a limited number of legislative days. It's just the nature of the beast," said Mike Feldman, a former top aide to Democratic then-vice president Al Gore.
"The notion of having a bill on his desk by August was never real. But if you don't set a timetable for Congress, there is no timetable, and they let it slide," said Norm Ornstein, an expert on congressional politics at the American Enterprise Institute think tank in Washington.
"It's complicated and it's much worse when you have to operate with a dwindling number of days and the possibility of something unexpected coming up that makes it more complicated. But it's doable," he told AFP.
Republicans and Democrats both plan to run advertisements in the home districts of swing-vote lawmakers during the recess, while congressional leaders map the next step in the pitched political battle in Washington.
Republicans point to public opinion polls showing growing unease with the Obama approach, which the party's chairman derided as "socialism" because of plans to increase the government's role in providing access to health care.
And they showcase the public's worries about the government deficit, which has ballooned to historic girth, and say voters are not prepared to sign off on another expensive Washington program.
Democrats point to deep public unhappiness with the health care status quo, support for Obama's plan from the leading American Medical Association, even as the president steps up a public relations campaign on his plan's behalf.
One critical but uncertain factor is the health of the battered US economy, according to independent political analyst Charlie Cook, writing in the National Journal public affairs magazine.
"Taking the time to fix the problems in the health care and climate-change bills while waiting for enough good economic news to make people feel a bit more comfortable with new spending might not be the worst thing for Democrats to do," he wrote.
White House Chief of Staff Rahm Emanuel predicted that Obama will sign legislation by the end of the year "that controls costs, expands coverage, and provides choice" but declined to light the path forward.
"I don't want to fast forward the movie; you're just going to have to watch the movie all the way through," he said.