The Supreme Court is hours away from delivering its most hotly anticipated ruling of the session, as the White House, lawmakers, business leaders and the nation wait to see if the Affordable Care Act will be upheld, struck down or some middle option.

For now, the decision remains anyone's guess, but it is sure to have sweeping consequences.

During an election year and a period of shaky economic recovery, what the high court decrees will ripple through the political world and, more importantly, the sector that counts for one-sixth of the American economy.

Will Americans be guaranteed coverage regardless of medical condition? Will they be forced to buy insurance? Will businesses be able to hire without worrying whether they can afford the accompanying health care costs?

The White House, peppered with questions at Wednesday's briefing, was reticent to entertain the implications of the looming decision and what it could mean for President Obama's signature domestic policy achievement and what it could mean for the millions of Americans it affects.

"We await the Supreme Court decision, as does everyone," Press Secretary Jay Carney said. "We will be ready for the decision when it comes down."

Carney said only that the Obama administration is "confident" the law is constitutional, and he defended what the provisions have done for health care in America to date. He said, for instance, that 3.1 million more young adults have coverage today because of a provision allowing them to stay on their parents' plans until age 26.

Republicans, though, say the myriad consumer protections come with a big cost, and they are vowing to keep up the fight to repeal the law should the court uphold all or part of it.

"If the court does not strike down the entire law, the House will move to repeal what's left of it," House Speaker John Boehner said Wednesday, claiming the law is driving up the cost of health care and making it tougher for small businesses to hire workers.

While Republicans' chief argument against the law is that it stifles economic growth with burdensome regulations, the chief legal argument in court is that the individual mandate requiring most Americans to get health insurance is unconstitutional.

There are several scenarios for court action on Thursday.

The Supreme Court could uphold the entire law or could strike down the entire law. In between those two extremes, the court could also rule that the individual mandate is unconstitutional -- while leaving the rest of the Affordable Care Act intact. A slight variation on that outcome would be for the court to strike down the mandate and two related provisions. Aside from the mandate, the law's expansion of Medicaid is at issue in Thursday's ruling, as well.

The high court could also surprise everybody and decide not to issue a ruling -- accepting the argument that because nobody has yet paid a penalty for failing to purchase health insurance, the case is not yet ripe for the courts to decide.

What comes next for the law is anybody's guess.

Republicans have vowed to repeal whatever's left, and Democrats have vowed to protect what they can.

"We're prepared to build on the landmark health reform to make sure, more and more, we have affordable quality health care for all Americans," Rep. Xavier Becerra, D-Calif., told Fox News.

But if the mandate is struck down, it throws the entire economic formula for implementing the policy out of balance. Health insurance companies are expected to take on a significant amount of additional cost due to provisions that guarantee coverage and implement other consumer protections -- in exchange, the mandate ensured those companies would get millions more customers. Without the mandate, that trade-off disappears.

Democrats have acknowledged that eliminating the mandate would cause problems for implementing the rest of the regulations.

Meanwhile, the decision could have a significant impact on the 2012 presidential race. If the law stands, Obama wins some measure of vindication -- but can also be assured that Romney will continue to run on repealing the policy. If the law falls, Obama faces a major rebuke, but can take solace in the fact that Romney can no longer run on his repeal pledge.

Romney, though, signaled Tuesday he'll be hammering the president over the law no matter how the court rules.

If the law is overturned, Romney said, "then the first three-and-a-half years of this president's term will have been wasted on something that has not helped the American people."

"If it is deemed to stand," Romney continued, "then I'll tell you one thing. Then we'll have to have a president, and I'm that one, that's going to get rid of ObamaCare."