By BRENT KENDALL, LOUISE RADNOFSKY and JESS BRAVIN

Associated Press
The Supreme Court will decide the fate of President Barack Obama's health-care law Thursday morning.
On the final day of its 2011-12 term, the high court will deliver its opinion on the Patient Protection and Affordable Care Act, which Mr. Obama signed on March 23, 2010. The first constitutional challenge to the law was filed that same day.
The central question before the court was whether Congress could require most Americans to carry health insurance or pay a penalty. The court could uphold the entire law, nullify part of it or strike it down completely.
All of Washington was prepared to react within minutes of the ruling, which was expected to come shortly after 10 a.m. EDT. Republicans said they would push to repeal any parts of the law that survived the court's review.
"Regardless of how the court rules, the law is a huge issue for the American people, and it has to be repealed completely," House Speaker John Boehner told House Republicans Wednesday, according to someone who was in the room.
White House officials have said they were confident the court would uphold the law, but they were preparing for other outcomes including pressing ahead with the remainder of the law if part is struck down.
The Supreme Court has three cases left to decide, and it may announce the other two rulings first. That is because many court watchers expect Chief Justice John Roberts to write the health-care opinion, and the court announces rulings in order of the seniority of the justice delivering the majority opinion. The chief justice has the highest seniority by virtue of his position.
The court will begin its session at 10 a.m. sharp. Usually on decision days, the court completes the release of opinions within a half-hour. After Thursday's final session of the current Supreme Court term, the justices aren't scheduled to take the bench again until October.
The Obama administration says the insurance mandate is legal because the Constitution gives Congress the power to tax and to regulate interstate commerce. Opponents say it is unprecedented for Congress to compel Americans to buy a particular product—in this case, health insurance—or be penalized.
If the court finds the insurance mandate unconstitutional, the consequences for the health-care law depend greatly on how much of the rest of the law survives. The court could leave the rest of the law intact, including two additional provisions requiring insurers to accept all customers and barring them from charging higher premiums to those who have pre-existing medical conditions. Insurers say that would cause chaos in the market because people might wait until they were sick to sign up for coverage.
The Obama administration said that if the mandate were nullified, the two other provisions should go as well. If the Supreme Court adopts that position, the ruling would cut out the heart of the law but still leave hundreds of other provisions intact, including those setting up marketplaces in 2014 for people to buy coverage.
Such a decision would likely lead to "enormous pressure on Congress and the states to restore some of the changes in the insurance market," said Larry Levitt, senior vice president at the nonpartisan Kaiser Family Foundation. Polling showed that the law's protections for sicker consumers were widely popular.
The Supreme Court could also strike down the entire law, as Justice Antonin Scalia suggested at March arguments. "My approach would say if you take the heart out of the statute, the statute's gone," Justice Scalia said, adding that Congress could then revive any portions if it wished.
Another possibility remained: The justices could dismiss the case as not ripe for adjudication, leaving the law intact for now. Some judges in lower courts said the penalty for those lacking health insurance qualified as a tax under the Anti-Injunction Act, a 19th-century law that says challenges to certain taxes can only be brought after the tax is paid.
If so, people couldn't challenge the insurance mandate until at least 2014, when it takes effect. However, the justices at March arguments suggested they didn't think the Anti-Injunction Act applied in this case.
—Anna Wilde Mathews contributed to this article.Write to Brent Kendall at [email protected], Louise Radnofsky at [email protected] and Jess Bravin at [email protected]