A legal challenge over whether Kansas will create a dual voter registration system has moved to federal court.

The Equality Kansas lawsuit seeks to block Secretary of State Kris Kobach from creating a dual registration system, arguing it would violate voters’ rights to equal protection. The American Civil Liberties Union is representing the group and voters.

U.S. District Judge Eric Melgren was assigned to the case Friday. Melgren is also presiding over separate litigation seeking to force modifications in the federal registration form. Both lawsuits stem from disputes over Kansas’ proof-of-citizenship law.

Under a dual system, people who use the state form and comply with the proof-of-citizenship rule could vote in any race. People who use the federal forms and don’t submit citizenship papers could vote only in federal races.