ATLANTA – Judges on a federal appeals court panel on Wednesday repeatedly raised questions about President Obama’s health care overhaul, expressing unease with the requirement that virtually all Americans carry health insurance or face penalties.

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, including Maine, 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.

Chief Judge Joel Dubina, who was tapped by President George H.W. Bush, struck early by asking the government’s attorney “if we uphold the individual mandate in this case, are there any limits on Congressional power?” Circuit Judges Frank Hull and Stanley Marcus, who were both appointed by President Bill Clinton, echoed his concerns later in the hearing.

Acting U.S. Solicitor Neal Katyal sought to ease their concerns by saying the legislative branch can only exercise its powers to regulate commerce if it will have a substantial effect on the economy and solve a national, not local, problem. Health care coverage, he said, is unique because of the billions of dollars shifted in the economy when Americans without coverage seek medical care. “That’s what stops the slippery slope,” he said.

Paul Clement, a former U.S. solicitor representing the states, countered that the federal government should not have the power to compel residents to buy to engage in commercial transactions. “This is the case that crosses the line,” he said.

Hull also seemed skeptical about the government’s claim that the mandate was crucial to covering the 50 million or so uninsured Americans.

She said the rolls of the uninsured could be pared significantly through other parts of the package, including expanded Medicare discounts for some seniors.