Nearly 100,000 Arizona residents have been found ineligible to vote in state and local elections due to a flaw in the voter registration system that incorrectly accepted duplicate driver's licenses as proof of citizenship. The error affects individuals who obtained their licenses before 1996, when proof of citizenship was not required, and later received duplicates. Maricopa County Recorder Stephen Richer has filed a lawsuit to limit these individuals to federal-only ballots, while Arizona Secretary of State Adrian Fontes argues against disenfranchising voters so close to the election. Both officials are seeking a ruling from the Arizona Supreme Court to resolve the issue. The flaw, which has existed since 2004, was discovered during routine checks and affects approximately 2.5% of Arizona's registered voters.