RICHMOND, Va. — A federal appellate court here has begun reviewing the decisions of two lower courts on the constitutionality of last year’s health care reform law.

The three appeals court judges, who were randomly selected from the 14 members of the U.S. Court of Appeals for the Fourth Circuit in Richmond, are looking at two cases in which federal court judges came to different conclusions about challenges to the law.

In one challenge, by Virginia Attorney General Kenneth Cuccinelli, Judge Henry Hudson of Federal District Court in Richmond ruled that by requiring most Americans to buy insurance — a commercial product — Congress had exceeded its authority to regulate interstate commerce.

In the other case, filed by Liberty University, Judge Norman Moon of Federal District Court in Lynchburg, Va., found that the mandate fell comfortably within “well-settled principles” set by the Supreme Court.

The three randomly selected appeals judges are all Democrats. Legal experts point out that the party of the appointing president is not necessarily predictive of a federal judge’s leanings but can give an indication.

In five decisions in lower courts, three Democrat-appointed judges have upheld the Obama administration’s Affordable Care Act, while two Republican-appointed judges have ruled that its central provision — the requirement that most Americans obtain health insurance — is unconstitutional.

During the opening day of the appellate court hearing, the three judges — Diana Gribbon Motz, who was appointed by President Bill Clinton, and Andre Davis and James Wynn Jr., who were appointed by President Obama — challenged both sides with pointed questioning.

Some court watchers said after the two-hour hearing that they felt the judges seemed to support the law’s constitutionality, including suggesting that the law could not work without the individual mandate.

The judges also said they were uncertain whether Virginia’s attorney general had legal standing to challenge the insurance mandate, because it would impose a requirement on individuals but not on states.

Virginia stakes its right to sue on its enactment of a state law aimed at exempting residents from the health insurance requirement, thereby creating a conflict with federal law. Lawyers for the administration countered that argument by stressing that states do not get to pick and choose which federal laws to follow.

“If you adopted this theory of standing you would allow, for example, a state that was opposed to the war in Afghanistan to say, ‘Our citizens should be exempt,’ and file a lawsuit on that basis,” United States Solicitor General Neal Katyal said.

The Virginia cases are the first of four scheduled for late May and early June.

The Court of Appeals for the Sixth Circuit in Cincinnati will hear arguments on June 1 in the appeal of a ruling upholding the law. A week later the Court of Appeals for the 11th Circuit in Atlanta will hear the Obama administration’s appeal of a Florida judge’s ruling that invalidated the entire act. That judge suspended his ruling until appellate courts could hear the case.

Most legal experts say they expect that the Supreme Court will ultimately settle the matter.