MADISON, Wis. (AP) — A federal judge said Wednesday that he won't rule before the election on a lawsuit that challenged a state law requiring college student IDs to have an expiration date in order for them to be used as a voter's ID.

U.S. District Judge James Peterson canceled a hearing he had scheduled for Thursday morning in the case, less than six weeks before the election in the hotly contested battleground state. Peterson said he didn't want to cause “chaos and confusion” by ruling in the case so close to the election, noting that absentee voting was already underway.

“If the court were to issue an order changing the status quo now, it would leave the (Elections) Commission and municipal clerks with little time to issue new guidance and retrain staff,” Peterson said. “The nearly inevitable appeal would mean weeks of uncertainty as the case was reviewed by the court of appeals and possibly the Supreme Court.”

He also said that any order could “lull student voters into complacency, believing that they now held an ID valid for voting, only to find out on the eve of the election that an appellate court had reached a different conclusion.”

Common Cause Wisconsin filed a lawsuit last year challenging the law enacted by the Republican-controlled Legislature in 2011, arguing that it was unconstitutional and that the information required to be on the IDs was irrational and unjustified.

Common Cause, as well as the state Department of Justice which defended the lawsuit, did not immediately respond to messages seeking comment.

Under the law, college student IDs can only be used for voting if they display the date they were issued, an expiration date that is no more than two years after the issuance date, and a signature.

Requiring an issuance and expiration date on the college ID is unnecessary, especially given that a number of other valid forms of voter ID never expire or remain valid indefinitely, the lawsuit said. Of the 28 states with voter ID laws that accept college or university campus IDs, Wisconsin is the only one where the student ID can only be valid for two years, the lawsuit said.

The lawsuit sought to allow any Wisconsin college photo ID at the polls.

Most colleges in Wisconsin had already changed their IDs to be in compliance with the law, a point the state Department of Justice made in arguing that the lawsuit should be rejected.

Those bringing the lawsuit have identified only six private colleges and two technical and community colleges that aren’t compliant, the judge said. They also haven’t identified any students who would be unable to obtain a compliant ID before the election, the judge said.

“Students at colleges that do not offer compliant IDs have time to get voting IDs through the avenues available to voters generally,” Peterson said.

Wisconsin's voter ID law was delayed for years, but it was ultimately upheld as legal by both the Wisconsin Supreme Court and a federal appeals court in 2014. The first major election where it was required was the spring 2016 presidential primary.

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