Lawmakers argue about whether a national data breach notification law should preempt 47 existing state laws. Congress hasn’t passed such a law in the U.S. over the past decade. Lawmakers will have to iron out conflicts about the scope of a new law. Trade groups TechAmerica, RILA and Acxiom call on Congress to preempt the 47 state laws that are already on the books. But some Democratic subcommittee members question whether such a national law should pre-empt all existing laws.”]