The Supreme Court's ruling on its biggest case — President Barack Obama's health-care reform — almost certainly will not be the last word on America's tangled efforts to address health-care woes.
The outcome also is likely to be a factor in the presidential campaign and help define John Roberts' legacy as chief justice.
The problems of high medical costs, widespread waste and tens of millions of people without insurance will require Congress and the president to keep looking for answers, whether or not the Affordable Care Act passes the test of constitutionality.
A look at potential outcomes:
Q: What if the Supreme Court upholds the law and finds Congress was within its authority to require most people to have health insurance or pay a penalty?
A: That would settle the legal argument, but not the political battle. The clear winners if the law is upheld and allowed to take full effect would be uninsured people in the U.S., estimated at more than 50 million.
Starting in 2014, most could get coverage through a mix of private insurance and Medicaid , a safety-net program. Republican-led states that have resisted creating health-insurance markets under the law would have to scramble to comply, but the U.S. would get closer to other economically advanced countries that guarantee medical care for their citizens.
Republicans would keep trying to block the law. They will try to elect likely presidential candidate Mitt Romney, backed by a GOP House and Senate, and repeal the law, although their chances of repeal would seem to be diminished by the court's endorsement.
Obama would feel the glow of vindication for his hard-fought health overhaul, but it might not last long even if he's re-elected.
The nation still faces huge problems with health-care costs, requiring major changes to Medicare that neither party has explained squarely to voters. Some backers of Obama's law acknowledge it was only a first installment: Get most people covered, then deal with the harder problem of costs.
Q: On the other hand, what if the court strikes down the entire law?
A: Many people would applaud, polls suggest.
Taking down the law would kill a costly new federal entitlement before it has a chance to take root and develop a clamoring constituency, but that still would leave the problems of high costs, waste, and millions uninsured.
Some Republicans in Congress already are talking about passing anew the more popular pieces of the health law.
But the major GOP alternatives to Obama's law would not cover nearly as many uninsured, and it's unclear how much of a dent they would make in costs. Some liberals say Medicare-for-all, or government-run health insurance, will emerge as the only viable answer if Obama's public-private approach fails.
People with health insurance could lose some ground as well. Employers and insurance companies would have no obligation to keep providing popular new benefits such as preventive care with no copayments and coverage for young adults until age 26 on a parent's plan. Medicare recipients with high prescription drug costs could lose discounts averaging about $600.
Q: What happens if the court strikes down the individual insurance requirement, but leaves the rest of the Affordable Care Act in place?
A: Individuals would have no obligation to carry insurance, but insurers would remain bound by the law to accept applicants regardless of medical condition and limit what they charge their oldest and sickest customers.
Studies suggest premiums in the individual health-insurance market would jump by 10 percent to 30 percent.
Experts debate whether or not that would trigger the collapse of the market for individuals and small businesses, or just make coverage even harder to afford than it is now. In any event, there would be risks to the health care system. Fewer people would sign up for coverage.
The insurance mandate was primarily a means to an end, a way to create a big pool of customers and allow premiums to remain affordable. Other forms of arm-twisting could be found, including limited enrollment periods and penalties for late sign-up, but such approaches probably would require congressional cooperation.
Unless there's a political deal to fix it, the complicated legislation would get more difficult to carry out. Congressional Republicans say they will keep pushing for repeal.
Without the mandate, millions of uninsured low-income people still would get coverage through the law's Medicaid expansion. The problem would be the 10 million to 15 million middle-class people expected to gain private insurance under the law. They would be eligible for federal subsidies, but premiums would get more expensive.
Taxes, Medicare cuts and penalties on employers not offering coverage would stay in place.
What If Insurers Don't Have to Cover Everyone?
Q: What if the court strikes down the mandate and also invalidates the parts of the law that require insurance companies to cover people regardless of medical problems and that limit what they can charge older people?
A: Many fewer people would get covered, but the health-insurance industry would avoid a dire financial hit.
Insurers could continue screening out people with a history of medical problems — diabetes patients or cancer survivors, for example. That would prevent a sudden jump in premiums. But it would leave consumers with no assurance that they can get health insurance when they need it, which is a major problem that the law was intended to fix.
Obama administration lawyers say the insurance requirement goes hand in hand with the coverage guarantee and cap on premiums, and they have asked the court to get rid of both if it finds the mandate to be unconstitutional.
One scenario sends shivers through the health care industry: The Supreme Court strikes down the mandate only, and delegates other courts to determine what else stays or goes.
Q: What happens if the court throws out only the expansion of the Medicaid program?
A: That would limit the law's impact severely because roughly half of the more than 30 million people expected to gain insurance under the law would get it through the expansion of Medicaid, the federal-state health insurance program for low-income people.
But a potentially sizable number of those low-income people still might be eligible for government-subsidized private insurance under other provisions. Private coverage is more expensive to subsidize than Medicaid.
States suing to overturn the federal law argue that the Medicaid expansion comes with so many strings attached it amounts to an unconstitutional power grab by Washington. The administration says the federal government will pay virtually all the cost and says the expansion is no different from ones that states have accepted in the past.
Q: What happens if the court decides that the constitutional challenge is premature?
A: The wild card, and least conclusive outcome in the case, probably also is the most unlikely, based on what justices said during oral arguments.
No justice seemed inclined to take this path, which involves the court's consideration of a technical issue.
The federal appeals court in Richmond, Va., held that the challenge to the insurance requirement has to wait until people start paying the penalty for not purchasing insurance. The appeals court said it was bound by the federal Anti-Injunction Act, which says federal courts may not hear challenges to taxes, or anything that looks like a tax, until after the taxes are paid.
So if the justices have trouble coming together on any of the other options they could simply punt.
The administration says it doesn't want this result. Yet such a decision would allow it to continue putting the law in place, postponing any challenge until more of the benefits are being received.
On the other hand, it might give Republicans more ammunition to press for repeal in the meantime.