WASHINGTON -- Different legal avenues are being taken by two pro-gun groups working to repeal D.C.'s 27-year-old ban on handguns. A case pending in federal court by the Cato Institute says the ban violates the Second Amendment. The National Rifle Association has a separate suit in another federal court, which also cites the Second Amendment argument and it also claims the ban violates due process and equal protection. Then last week, Utah Sen. Orrin Hatch introduced legislation to repeal the ban. A spokesman for the gun-control group Violence Policy Center said infighting is unusual for gun-rights advocates. According to The...