The House of Representatives early on Sunday brought the federal government closer to a shutdown as it voted to delay President Barack Obama's landmark healthcare law for a year as part of an emergency spending bill.
By a mostly partisan vote of 231-192, the Republican-controlled House approved the "Obamacare" amendment, despite a veto threat from the White House.
It also voted 248-174 to repeal a medical device tax that aims to help fund healthcare programs under the 2010 law.
And in a sign that lawmakers might be resigned to a government shutdown beginning Tuesday, the House unanimously approved a bill to keep paying U.S. soldiers in the event the government runs out of money to run many programs.
Senate Majority Leader Harry Reid reiterated on Saturday that the House bill would be dead on arrival in the Democratic-controlled Senate, which is not scheduled to meet until 2 p.m. on Monday.
Obama also threatened to veto any bill that delays his healthcare restructuring.
There is a slight chance the two sides could reach a funding deal before the government's fiscal year ends at midnight on Monday. Congress could also act at any time to end the impasse if a shutdown did occur.
But the bitterness of the House debate on Saturday night that spilled into early Sunday did not bode well for prospects of a compromise.
"You have been hijacked by a group called the Tea Party," Democratic Representative David Scott of Georgia said angrily, referring to the powerful conservative, anti-government movement that holds significant sway over Republicans.
"The American people deserve to have time to see what this monstrosity will do before it is implemented," shouted Republican Representative John Culberson of Texas, referring to "Obamacare."
The high-stakes maneuvering between Democrats and Republicans is likely to continue through much of Monday.
The standoff is also a harbinger for the next big political battle in Washington: a far more consequential bill to raise the federal government's borrowing authority. Failure to raise the debt ceiling by mid-October could result in the government defaulting on its obligations.
MEDICAL DEVICE TAX
The funding impasse is the culmination of more than three years of failed conservative efforts to repeal "Obamacare," a program aimed at extending health insurance to millions of those without coverage.
Republicans argue that "Obamacare, which is set to launch on October 1, is a massive and unnecessary government intrusion into medicine that will cause premiums to skyrocket and damage the economy.
Failure to pass a funding bill would close down much of the government for the first time since 1996. More than a million federal employees would be furloughed from their jobs, with the impact depending on the duration of a shutdown.
The current timetable could leave House Speaker John Boehner with the most difficult decision of his career: whether to approve a straight-forward spending bill passed on Friday by the Senate or allow the government shutdown to begin.
Neither side wants to be the last to cast the final vote that would lead to a shutdown, a concern that has turned the funding measure into a hot potato tossed between the two chambers.
While polls consistently show the American public is tired of political showdowns and opposed to a shutdown, House conservatives were jubilant about the fight.
"This is a win-win all the way around," said Republican Arizona Representative Matt Salmon, who described the mood of Republicans before the vote as "ecstatic."
Republicans and a handful of Democrats also approved an amendment to the bill repealing a tax on medical devices that helps fund the healthcare law to the tune of about $30 billion. That provision, sought with heavy lobbying by the medical device industry, has been supported in the past by some Democratic senators.
In a government shutdown, spending for functions considered essential, related to national security or public safety, would continue along with benefit programs such as Medicare health insurance and Social Security retirement benefits for seniors.
But civilian federal employees - from people who process forms and handle regulatory proceedings to workers at national parks and museums in Washington - would be temporarily out of work.
The last government shutdown ran from December 16, 1995 to January 6, 1996, and was the product of a budget battle between Democratic President Bill Clinton and Republicans, led by then-Speaker Newt Gingrich.
Republicans suffered a public backlash when voters re-elected Clinton in a landslide the following November, a lesson never forgotten by senior Republicans, including Boehner.
This time, Boehner tried to avoid a showdown but was overruled by his rebellious caucus, largely influenced since the 2010 election by newcomers endorsed by the Tea Party.
While Boehner and Majority Leader Eric Cantor, the top House Republicans, worked behind the scenes, they did not deliver floor speeches in support of the bill - something they often do on major legislation.
Instead, some of the House's most conservative members who drove the "Obamacare" delay effort, dominated the debate.
With Boehner effectively sidelined, rank-and-file Republicans boasted of their unity. Members chanted, "Vote, vote, vote, vote," in their closed-door meeting, they reported later.
Afterward, Democratic Representative Louise Slaughter of New York, took to the House floor to accuse Republicans of throwing a "temper tantrum" about "Obamacare" under pressure from "Tea Party extremists."
Conservative and liberal groups, from the Tea Party to women's rights organizations, have been cashing in on the showdown over "Obamacare," using it to rally supporters and raise money for next year's congressional elections.