US Republicans vowed to dismantle President Barack Obama's landmark health care reforms regardless of how the Supreme Court rules on Thursday, with Mitt Romney pledging to "repeal and replace" the law if he wins the White House.
The high court's nine justices have deliberated over the constitutionality of the 2010 legislation, and whether they opt to strike down all, part or none of it has been the talk of political and health care industry circles for weeks.
"We're all waiting to see how the court will decide," Romney told supporters at a Wednesday campaign rally in this Washington suburb of Sterling, in the battleground state of Virginia.
"We already know it's bad policy and it's got to go. And so if the court upholds it, if they say, 'look, it passes the Constitution,' it still is bad policy, and that'll mean, if I'm elected, we're going to repeal it and replace it," he said to loud applause.
"If, on the other hand, the court strikes it down, they'll be doing some of my work for me."
With all eyes turned to the high court, and growing numbers of Republicans believing it might invalidate at least some of the law, Romney suggested Obama and company were feeling the heat.
"My guess is, they're not sleeping real well at the White House tonight," he quipped.
Lawmakers on both sides of the aisle have been bracing for weeks for the momentous decision, which could have major implications for November's presidential election.
Obama claims the reform as his singular domestic achievement, while Romney has made the repeal of what he derisively calls "Obamacare" a top pledge on the campaign trail.
Several Republican lawmakers backed Romney's position, including House Speaker John Boehner, who said bluntly that "if the court does not strike down the entire law, the House will move to repeal what's left of it".
Conservative Jeb Hensarling insisted there were "profound constitutional reasons" why the law should be struck down, and serious economic reasons for the House to scrap it should it be allowed to stand.
"If the Supreme Court doesn't see fit to deem it unconstitutional, House Republicans are going to repeal it lock, stock and barrel," he said.
Cathy McMorris-Rogers, a rising star within the Republican leadership and Romney's pointwoman in Congress, struck a softer tone, saying that "no matter how the court rules, Republicans are ready to move forward with a different approach on health care reform."
She said her party was helping forge "common-sense, step-by-step, bipartisan solutions to health care, and we hope that the president and Democrats will work with us."
The Affordable Care Act insures an extra 32 million Americans, prevents coverage from being refused on the basis of patients' medical histories and allows children to remain on their parents' health care plans until age 26.
At the heart of the law lies the individual mandate that requires every US citizen from 2014 to take out health insurance or be subject to a fine.
Opponents argue that Congress overstepped its constitutional prerogatives in requiring individuals to buy insurance, while the Obama administration contends that the move is vital and in line with existing trade and tax law.
Despite Republican claims that it will increase costs, the non-partisan Congressional Budget Office says it would reduce the ballooning US deficit a little over the first decade and substantially more over the second.
Republican congressman Ben Quayle said he hoped the court would invalidate the law in its entirety so there would be "a clean slate" to go about reforming health care and implementing some Republican plans such as helping small businesses band together to buy insurance.
"If we actually make sure that we're allowing people to buy insurance across state lines, making insurance attached to the person rather than the job, allowing states to have pools with pre-existing conditions... I think (that) will actually drive down costs and increase access," Quayle told CNN.