Republicans have asked the Supreme Court to stop 40,000 voters who have no proof of citizenship from casting ballots in the 2024 presidential race.
Democrats are furiously opposed to the request, which could tip the scales in a crucial swing state that Joe Biden carried by 10,000 votes in 2020.
The dispute in Arizona has to do with a conflict between state and federal law on proof of citizenship. Arizona started requiring proof to register in 2004, but in 2013, the Supreme Court found the requirement was preempted by the federal "motor voter" law signed by Bill Clinton.
At the time, the Court ruled that the National Voter Registration Act requires all states to "accept and use" the standardized federal form, which asks for a sworn declaration of citizenship. However, no proof is required.
While Arizona has allowed voters who use the federal form to vote in federal elections, Republicans in 2022 passed a law to restrict these "federal only" voters from casting ballots in presidential elections or voting by mail. The law was immediately challenged and has yet to take effect.
Defending the law to the Supreme Court, the Republican National Committee says Congress cannot override "the Arizona Legislature’s sovereign authority to determine the qualifications of voters and structure participation in its elections."
Democrats have dismissed concerns about non-citizens voting as exaggerated and rooted in conspiracy theories. But in a battleground like Arizona, even a small number of illegal votes could make a big difference.
Arizona Secretary of State Adrian Fontes (D) says Republicans want the Supreme Court to disenfranchise 41,000 lawful voters based on unfounded theories of fraud.
"There is no evidence of fraud and undocumented voting. The 2024 election is weeks away and acting now to restrict the voting rights of a large group of Arizona's voters is undemocratic," Fontes said.
Republicans want the Supreme Court to step in by Thursday before counties start printing ballots. The Biden administration argues it would be disruptive to require proof of citizenship this late in the game.
"Thousands of voters have already registered to vote by filing the federal form without accompanying documentary proof of citizenship," said Solicitor General Elizabeth Prelogar. "Judicial intervention at this stage would produce unnecessary confusion and chaos on the cusp of an election."