A federal judge ruled Sunday that Iowa election officials can continue their ballot challenges of more than 2,000 voters suspected of being noncitizens attempting to vote based on an outdated Iowa Department of Transportation database.

In late October, Iowa Secretary of State Paul Pate directed county auditors to challenge the ballots of 2,176 voters who had previously indicated they were noncitizens on an Iowa DOT form.

Johnson County Auditor Erin Shane, on Friday, found that 63 of the 295 on the list provided to her office had proved they were naturalized U.S. citizens.

The American Civil Liberties Union of Iowa filed a lawsuit Thursday on behalf of four voters who were affected by the challenges and are naturalized citizens. The group alleged that the directive violated federal voting rights and violated several constitutional rights of naturalized citizens on the list.

During a hearing on Friday at the federal courthouse in Des Moines, the state argued it had the duty to ensure noncitizens were not voting in the election and that the challenges did not present an undue burden since they were not canceling voter registration. The directive instead challenged the ballots requiring those voters to vote a provisional ballot until they could prove their citizenship.

Judge Stephen Locher wrote in his Sunday ruling that both sides can agree that some of those on the list are noncitizens.

“This portion appears to be relatively small — no more than 12 percent — but, still, the injunctive relief requested by Plaintiffs effectively would force local election officials to permit those individuals to vote,” Locher wrote. “Whatever concerns Plaintiffs might have about the nature and timing of Secretary Pate’s letter, it

would not be appropriate for the Court to respond by granting injunctive relief that effectively forces local election officials to allow ineligible voters to vote.”

In a statement on Sunday evening, Iowa Attorney General Brenna Bird, whose office represented the state in the matter, said the ruling is a victory ensuring only American citizens can vote in Iowa elections.

“Today’s court victory is a guarantee for all Iowans that their votes will count and not be canceled out by illegal votes,” Bird said. “I was glad to lead the fight in court to defend Iowa’s long-standing election integrity laws.”