Virginia Gov. Ralph Northam’s push to ban the sale of assault weapons failed on Monday after some of his fellow Democrats balked at the proposal. Four moderate Democrats joined Republicans in Monday’s committee vote, rejecting legislation that would have prohibited the sale of certain semiautomatic firearms, including popular AR-15 style rifles, and banned the possession of magazines that hold more than 12 rounds. The bill was a top priority for Northam, who has campaigned heavily for a broad package of gun-control measures.