A federal appeals court in Chicago ruled Tuesday that the Second Amendment doesn't bar state or local governments from regulating guns, adopting the same position that Judge Sonia Sotomayor, President Barack Obama's nominee to the Supreme Court, did when faced with the same question earlier this year.

Last year, the U.S. Supreme Court cited the Second Amendment to strike down a handgun ban adopted in 1976 by the Washington, D.C., City Council. The court, by a 5-4 vote, found that the amendment protected from federal infringement...