WASHINGTON — A U.S. appeals court ruled Tuesday that the federal law banning handgun sales by licensed dealers to anyone under 21 is unconstitutional.A panel of the U.S. Court of Appeals for the Fourth Circuit, based in Richmond, Virginia, voted 2-1 to declare the law invalid. "Our nation's most cherished constitutional rights vest no later than 18. And the Second Amendment's right to keep and bear arms is no different," the majority opinion said.The ruling, sure to be appealed, was a victory for a Virginia woman, Natalia Marshall. She wanted to buy a handgun to protect herself from her abusive...