evidence: The tool is a shared database called the Electronic Registration Information Center, or ERIC for short. It allows states to securely share voter registration data across state lines and with a number of other government agencies, like the Social Security Administration and departments of motor vehicles. [...] "When you move away from a state, you don't call your old state and say, 'Please take me off the voter lists,' " said David Becker, an elections expert and former Justice Department attorney who led the development of ERIC while working at the Pew Charitable Trusts. "So to get really strong data that someone moved to another state — got a driver's license there or maybe registered to vote — that's really powerful information that allows states to keep their data up to date." [...] But that bipartisan unity is being tested, as some pockets of conservative media have ignited a pressure campaign against ERIC.