https://en.wikipedia.org/wiki/Interstate_Voter_Registration_Crosscheck_Program
Interstate Voter Registration Crosscheck (commonly referred to as IVRC or Crosscheck) was a database in the United States which aggregated voter registration records from multiple states to identify voters who may have registered or voted in two or more states. Crosscheck was developed in 2005 by Kansas Secretary of State Ron Thornburgh in conjunction with Iowa, Missouri, and Nebraska. In December 2019, the program was suspended indefinitely as part of a settlement[1] of a lawsuit filed by the American Civil Liberties Union of Kansas challenging Kansas' management of the program. Prior to Crosscheck's legally mandated suspension, a dozen states had withdrawn from the program citing the inaccurate data and risk of violating voters' privacy rights. Crosscheck was also accused[2] of facilitating unlawful purges of voters in a racially discriminatory manner.