All three judges on the 11th Circuit Court of Appeals panel questioned whether upholding the landmark law could open the door to Congress adopting other sweeping economic mandates. The panel is made up of two Democratic appointees and one Republican appointee.

The Atlanta panel did not immediately rule on the lawsuit brought by 26 states, a coalition of small businesses and private individuals who urged the three to side with a Florida judge who struck down the law. And it's never easy to predict how an appeals panel will decide.

But during almost three hours of oral arguments, the judges asked pointed questions about the so-called individual mandate, which the federal government says is needed to expand coverage to tens of millions of uninsured Americans. With other challenges to the law before other federal appeals courts, lawyers expect that its fate will ultimately be decided by the U.S. Supreme Court.