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The world will have to wait a few more days to hear the verdict on ObamaCare.

After ruling Monday on Arizona's immigration law, the Supreme Court appears likely to rule on the federal health care overhaul on Thursday. That's the next day justices are scheduled to announce opinions, and is expected to be the final day for rulings.

In releasing the health care verdict, the Supreme Court will be ending a momentous session.

The health care ruling, as campaign advisers are well aware, has the potential to re-shape this year's presidential race. For weeks, each party has been positioning itself to make the best of whatever outcome emerges from the tight-lipped justices.

And the implications go far beyond the 2012 election. The outcome of the health care case, involving one of the most divisive domestic policies in modern times, will affect millions of Americans. Calling for the law's survival, supporters trumpet the expanded consumer protections and subsidies that make insurance more available and affordable. Calling for its defeat, critics blast what they describe as an unconstitutional requirement to buy health insurance, and warn the law will pummel businesses with its mandates and fines.

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In the run-up to the historic ruling, each party is crafting a game-plan.

House Speaker John Boehner this past week cautioned the GOP ranks against "spiking" the ball if the mandate is struck down. He and other Republicans say the party will remain focused on repealing whatever parts of the law remain following the upcoming ruling. And, they say, they'll pursue "step-by-step" reforms to replace the law no matter the court's decision.

Lawmakers are dealing with plenty of other matters this week. In addition to Monday's decision reining in Arizona on its immigration law, the House could vote to hold Attorney General Eric Holder in contempt. On health care, they're trying to game out all scenarios.

In a memo to colleagues, House GOP Conference Chairman Jeb Hensarling, R-Texas, urged members to prepare for three possible rulings: a full repeal, a partial repeal involving the mandate or a law left intact.

He advised members to schedule time to read the entire decision, prepare statements for all three scenarios and consider scheduling tele-town halls with constituents.

"No matter how the Supreme Court rules, this is going to be a seismic decision," said Michael Cannon, of the Cato Institute. "If they uphold the individual mandate, if they strike down the individual mandate -- either way, they will be defining the relationship between the government and the citizens for decades to come."

While publicly expressing confidence that the law will be upheld, both the White House and congressional Democrats are said to be quietly planning for the possibility of at least a repeal of the mandate.

House Democratic Leader Nancy Pelosi admitted that this outcome could threaten the entire law. "You have to have the mandate in order for this to work from a financial standpoint," she said.

Because new coverage requirements put a financial burden on insurance companies, the mandate was meant to allay that strain by sending millions of new customers their way. Without the mandate, that formula falls apart.

Democrats, though, are holding out hope that benefits of the health care law will stand regardless of the decision.

Pelosi suggested that if the federal mandate goes, states might still be able to step in with their own individual requirements -- citing the mandate in Massachusetts, the state Mitt Romney used to govern.

Rep. Xavier Becerra, D-Calif., speaking on ABC's "This Week," said some of the protections are here to stay no matter what.

"I believe most Americans will say, 'we're never going to go back to those days where my child could be denied access to my health insurance because he or she has a pre-existing condition,'" he said.

Becerra also questioned whether people will wonder if the Supreme Court has "become a political body" should it strike down the law.

The comment underscored how Democrats may react should the decision come down in Republicans' favor -- by vilifying the court itself.

The political implications of the ruling, though, are unclear. If the court strikes down all or part of the law, it's a major blow to Obama, but also diminishes the issue as a wedge for Romney in the 2012 campaign. If the court upholds the law, it's a victory for Obama but also ensures Romney can run on a promise to repeal the law in 2013.

Fox News' Doug McKelway contributed to this report.