A number of states have challenged the constitutionality of the law's requirement that most Americans obtain health insurance or pay a penalty. The rulings have been divided, and the issue is certain to end up before the U.S. Supreme Court.
A U.S. District Court judge in Florida ruled the entire law unconstitutional, while a U.S. judge in Virginia ruled the insurance mandate unconstitutional and upheld the rest of the law. Other courts have dismissed cases or have found the law's mandate to purchase insurance constitutional.
The U.S. Supreme Court could decide as early as next year. Senate Finance Committee Chairman Max Baucus, who played a leading role in writing the healthcare law, and other healthcare advocates believe the law will be upheld.
Conservative critics give better than even odds that the Supreme Court will overturn the law.
If the court does decide that the coverage mandate violates the Constitution, many experts believe the judges would most likely strike down just that provision and leave the rest of the law intact.
A decision striking down the purchase mandate but leaving intact provisions requiring insurers to cover everyone regardless of medical history would wreak havoc on the insurance industry and send premiums soaring.
The law's major provisions establishing state insurance exchanges, imposing coverage mandates and requirements that insurers can no longer exclude or charge more for preexisting conditions take effect in 2014. That would give lawmakers time to act on any court decision.
