The U.S. Supreme Court has upheld a provision of Arizona's law requiring proof of citizenship for voter registration in a 5-4 ruling. This decision allows enforcement of regulations that could affect thousands of voters just months before the November presidential election, where Democratic Vice President Kamala Harris is set to face former President Donald Trump. The court's ruling was in response to an emergency request from the Republican National Committee and Arizona Republicans seeking to implement stricter voter registration measures enacted in 2022. While the court blocked efforts that could have barred over 41,000 voters from casting ballots, it reinstated the law mandating rejection of state voter registration forms lacking citizenship proof. The dissenting justices included three liberals and conservative Justice Amy Coney Barrett, while the ruling was supported by Chief Justice John Roberts and four other conservative justices. Legal challenges surrounding the law are expected to continue in lower courts.