The federal Justice Department is refusing to support a U.S. elections official who sided with Kansas, Alabama and Georgia in a fight over whether voters should have to show proof of citizenship.

The government contends in a court filing that the executive director of the U.S. Election Assistance Commission strayed from federal law when he required citizenship proof for people in those three states who register using a national form.

Residents of other states only need to swear that they are citizens, not show proof.

The Justice Department is siding with voting rights group in urging a federal judge to temporarily block the proof-of-citizenship requirements for residents in the three states.

The election assistance commission’s director Brian Newby had granted the states’ request to change form’s instructions for their residents.