WASHINGTON – In this city of rumors and leaks, it has been an excruciating lead-up to the Supreme Court ruling on President Obama’s health care law. The decision is days away, but no one knows precisely when it will come or what it will say.

Behind the scenes, Republicans and Democrats are strategizing about what to do in the moments and days after the most consequential high court decision in a generation – a ruling that will reverberate politically and in the lives of everyday Americans.

At issue is Obama’s signature legislative achievement, an expansive revision of the nation’s health care system that the court could uphold, throw out or something in between – allowing much of the law to stand, for example, but striking down the requirement that individuals buy insurance.

On Capitol Hill, congressional Republicans have worked hard to synchronize their messages and communicate with presidential candidate Mitt Romney in hopes of getting a political bounce from the ruling, no matter which way it goes. Their plan is to immediately attempt to repeal what might remain of the legislation. Then, step by step, they would propose smaller measures.

In the Obama administration, which has largely declined to entertain questions about what might happen if the court rules against the law, Health and Human Services Secretary Kathleen Sebelius recently acknowledged that officials are prepared for that possibility.

“We’ll be ready for court contingencies,” she told a women’s health roundtable.

White House allies already are offering their spin in the event that only the “individual mandate” is overturned. Their message: The rest of the law could still succeed.

“Is the mandate important? Yes,” said Ronald Pollack, head of Families USA, one of the key consumer groups that helped craft the measure. “Is it the most controversial provision in the Affordable Care Act? Most certainly. But is it the heart of health reform? No, not even close.”

Although polls show that Americans are stubbornly divided over the measure, parts of it remain very popular, and many Democrats and Republicans agree that something must be done to rein in ballooning health care costs.

Republicans, whose opposition to the legislation has been a rallying cry, sense a political opportunity in the wake of the court ruling.

In a May 31 memo, House Speaker John A. Boehner, R-Ohio, offered GOP members talking points to answer what the party would do if the court strikes down all or part of the law.

A key point: “Republicans will not repeat the Democrats’ mistakes. We won’t rush to pass a massive bill the American people don’t support.”

Some Republicans privately express worry that an immediate attempt to repeal what is left of the law would put them on the record as opposing some of the more popular aspects, such as requiring coverage of pre-existing conditions and allowing young people to stay on their parents’ insurance plans through age 26.

Eager to show that he recognizes the need for reform, Romney reiterated this week that he would repeal Obama’s law and elaborated on a health plan he proposed earlier that he said would look more like a “consumer market” rather than a “government-managed utility.” He also promised to divert some federal health care spending to state governments.

Top providers, such as United Healthcare, Humana and Aetna, have rushed in recent days to reassure their customers that if the entire law is overturned, the companies will continue to offer preventive services without co-pays and allow adult children to remain on their parents’ plans.

But the most prominent insurance trade group, America’s Health Insurance Plans, has been making the case that if only the individual mandate is invalidated and the rest of the law is left intact, premiums will rise and the insurance market for individuals will implode.

“Our focus is making sure people understand the inextricable link between the coverage requirement and the market reforms,” said Robert Zirkelbach, spokesman for the organization.