A US federal appeals court in Virginia began Tuesday examining two challenges to President Barack Obama's controversial health care law.
It's the first time any challenge of the law, one of Obama's key domestic achievements, has reached the federal appeals court level. Legal experts predict that ultimately the US Supreme Court will decide the matter.
The law, extending coverage to 32 million uninsured Americans, has been bitterly debated and challenged across the United States since Congress passed it last year.
Opponents say a key provision known as the "individual mandate" exceeds Congress's regulatory powers by requiring Americans to either purchase health insurance by 2014 or pay a fine.
On Tuesday, the appeals court heard arguments in the state of Virginia's case, which says forcing people to buy health insurance is unconstitutional. A lower court agreed with the state's argument, which led to the appeal.
The state of Virginia had passed a law specifically stating that residents cannot be forced to buy health insurance.
Another complaint against the health care law mandate was filed by the Liberty University, located in Virginia. A lower court had ruled against the Christian-based university's argument.
The three appeals court judges randomly selected to hear the cases all were appointed by Democratic presidents, which could benefit Obama and the law's supporters.
A decision is expected at the end of the summer.
On April 25, the Supreme Court rejected Virginia's request to immediately rule on whether the law is constitutional.
It marked the second time the nation's highest court denied a request from critics of the law for an expedited review, without the issue being examined thoroughly in appeals courts first.
Two Republican-appointed federal judges -- in Virginia and Florida -- have already declared the law unconstitutional.
But, in another sign of how the rulings have been largely split along party lines, three Democratic appointees have upheld the law -- in Michigan, Virginia and the US capital Washington.
Explore further: CDC presents recent trends in health behaviors of US adults