The D.C. voting rights bill adopted by the U.S. Senate includes an amendment offered by Republican Sen. John Ensign of Nevada that repeals the city’s ban on semiautomatic weapons, repeals all registration requirements, removes criminal penalties for the possession of unregistered firearms and legalizes carrying a gun on the streets. “I am hopeful that the Ensign amendment will not pass,” Mendelson said. “It would be a serious blow to public safety.”What public safety would that be?