The United States Supreme Court on Thursday ruled that Arizona can enforce part of a voter registration law that is being challenged in federal court, effectively allowing the state to bar legal voters from registering just about 10 weeks before the election.

In a split decision, the high court handed a win to the Republican National Committee and Arizona legislative leaders Ben Toma, the speaker of the state House of Representatives, and Warren Petersen, the state Senate president. In a 5-4 decision via an unsigned order. The court reinstated a portion of the law that allows the state to stop accepting state-created voter registration forms from Arizona residents unless they provide proof of citizenship.

The brief order did not explain the reasons for the court’s decision, which is common for emergency rulings. Conservative Justice Amy Coney Barrett sided with the court’s three liberal justices.

“Unlike voter ID laws, that often have not been shown to have a big effect on turnout, these documentary proof of citizenship laws matter a lot,” Hasen wrote. “They stand to literally disenfranchise thousands of eligible voters for no good reason.”

The Campaign Legal Center wrote that it filed the lawsuit challenging the law on behalf of Native, Latino and student voters, some of whom would be disproportionately impacted by the law.

The CLC emphasized that election officials in Arizona already have systems in place to verify voter eligibility, and work to ensure the voter rolls are accurate and up to date.