The U.S. Supreme Court declined Monday to take up an appeal attempting to reinstate Kansas’ requirement that residents prove their citizenship before being able to register to vote.

The high court denied the appeal without explanation, meaning the ruling from a lower court in 2018 striking down the law will stand.

The measure, championed by former Secretary of State Kris Kobach, was passed in 2011 with broad bipartisan support and required a birth certificate or passport be presented to register to vote. It hadn’t been enforced since 2016 because of the legal proceedings.

Attorney General Derek Schmidt and Scott Schwab, Kobach’s successor as secretary of state, appealed in June to the nation’s highest court in an effort to revitalize the law.

Schmidt’s office acknowledged the legal challenge had reached the end of the road and said it would be up to lawmakers to determine a way forward.

"The Kansas statute requiring documentary proof of citizenship when registering to vote passed the Legislature with overwhelming bipartisan majorities, and we vigorously defended it on appeal," John Milburn, a spokesperson for the Attorney General’s Office, said in a statement. "But with today's decision no options for further legal defense remain and the Legislature will need to determine how to proceed in light of the judicial rulings."

Schwab said that realistically the Legislature probably wouldn’t address the issue this session but noted it would be worth considering.

"We do need to review that law and find a way to do constitutional measures to make sure a person who is registering to vote is a qualified elector," he said. "At the end of the day that is the whole point."

After its introduction, the requirement was blamed for the suspension of thousands of voter registration applications, as residents didn’t necessarily have the right documents to prove their citizenship.

Kobach personally defended the law in federal court, even infamously being held in contempt by a U.S. District Court judge for behaving "disingenuously" during the case proceedings.

The controversial former secretary of state said he was hopeful the high court would hear the state’s appeal. The U.S. Court of Appeals affirmed the lower court ruling in April that the law was an undue burden on the rights of Kansans to vote.

Dale Ho, director of the ACLU’s Voting Rights Project and the nonprofit’s lead attorney challenging the law, slammed Kobach’s legacy in a statement supporting the Supreme Court’s decision.

"Tens of thousands of Kansas voters were illegally denied the most fundamental right in our democracy because of this law," Ho said. "The Supreme Court’s decision not to review the case will finally close this chapter on Kris Kobach’s sorry legacy of voter suppression."