A three-judge panel selected at random to hear oral arguments in two cases challenging the constitutionality of the federal health care law in Richmond on Tuesday included only judges appointed by Democratic presidents.

Of the 14 judges who sit on the U.S. Court of Appeals for the 4th Circuit, seven were appointed by Republicans and seven by Democrats.

But the panel selected by a computerized lottery to hear Tuesday’s health care lawsuits was composed of Judge Diana Gribbon Motz, appointed to the bench by President Clinton and Judges Andre M. Davis and James A. Wynn Jr., who were both appointed by President Obama.

The three judges heard more than two hours of arguments in two separate cases and frequently appeared skeptical of arguments advanced by parties seeking to invalidate the law.

One of the suits was brought by Liberty University, a private religious college in Lynchburg. The other was brought by Virginia Attorney Gen. Ken Cuccinelli (R) on behalf of the state.

Both cases argue that Congress exceeded its constitutional authority to regulate interstate commerce with a provision of the law that requires individuals to obtain health insurance by 2014 or pay a penalty.

The lawsuits are two of the more than 30 legal challenges to the federal law that have been filed. An appeals court in Atlanta is scheduled to hold oral arguments in Florida next month on a challenge filed jointly by 26 states.

Republicans have turned to the legal challenges as their best hope to wipe away the federal legislation. The law’s constitutionality will ultimately be determined by the U.S. Supreme Court.

The judges offered no indication of how long they will take to rule in the cases, which resulted from appeals of contradicting lower court decisions. One federal judge upheld the constitutionality of the law in a ruling on the Liberty case while a separate federal judge hearing Virginia’s lawsuit found that the law was unconstitutional.

The judges seemed particularly dubious of Virginia’s assertion that it has standing to sue in the case. A lower court judge had previously accepted Cuccinelli’s contention that Virginia has a sovereign interest in protecting a state law passed last year by the General Assembly that makes it illegal to require Virginians to be insured.

“How on earth can there be standing if all it takes to establish standing is that the state pass a law and the attorney general moves forward?” Judge Davis at one point asked Acting Solicitor General Neal Kumar Katyal, defending the law on behalf of the Obama administration.

The judges also asked probing questions of Mathew D. Staver, a lawyer for Liberty University, challenging Staver’s assertion that a citizen who goes without health insurance has chosen not to engage in economic activity and can’t be forced to take part in the market with a government mandate.

“What in the commerce clause is going to require activity?” asked Judge Motz. “Does it mention activity?”

“I think it’s inherent when you talk about regulating commerce. . .commerce cannot be idleness,” Staver responded.

Katyal countered that, in fact, an individual who goes without insurance nevertheless takes part in the vast health care market, when he or she sickens or is injured and shows up for medical care. He noted that uncompensated care costs $43 billion a year and raises the average family’s health care premium by $1,000.

“It’s an almost universal factor of our existence,” Katyal said. “One cannot opt out of it on an individual basis.”

The hearing took place in a Richmond courtroom packed with reporters, law clerks, professors, federal and state officials. Advocates for and against the law held dueling press conferences outside.

In a statement, White House spokeswoman Stephanie Cutter said the administration is “confident the various cases regarding the law will be decided quickly, long before the law is scheduled to be fully implemented” and said administration officials are “confident” they will prevail.

Cuccinelli will hold an afternoon press conference to discuss the hearing.