In his 15 years on the federal appeals court in Philadelphia, Judge Samuel A. Alito Jr. has provided just a few direct statements on the intense legal debate over how power should be shared between the federal government and the states.

To some scholars, those occasions have been revealing and significant and suggest that if confirmed to the Supreme Court, Judge Alito might be an aggressive leader in expanding state authority at the expense of the federal government.

In 1996, Judge Alito voted to strike down a recently enacted federal law that limited the possession of machine guns, in the case of United States v. Rybar. In his dissent from the opinion of the three-judge panel of the United States Court of Appeals for the Third Circuit, he said a gun dealer in Pennsylvania should not have been convicted because Congress did not constitutionally have the right to enact the law on machine guns.

In that case, Judge Alito relied on a Supreme Court ruling from 1995, United States v. Lopez, that struck down a federal law providing strong penalties for possessing guns in the immediate vicinity of a school. He not only disagreed with judges on the appeals court, but also those of at least three other circuit courts that upheld the law on machine guns.