By Sahil Kapur

The Supreme Court on Monday overturned an Arizona law that required proof of citizenship to register to vote, declaring that state efforts of the sort are trumped by a federal statute commonly known as the “motor voter” law.

The National Voter Registration Act of 1993 required states to accept a voter registration form that lets people register to vote with basic identification when renewing their driver’s license or applying for social services. The registration form requires prospective voters to attest that they are U.S. citizens but doesn’t require them to provide proof of citizenship. The Court concluded that Arizona may not require such additional information.

The 7-2 decision in Arizona v. Inter Tribal Council was written by Justice Antonin Scalia. Justices Clarence Thomas and Samuel Alito dissented from the majority.

“We hold that [federal law] precludes Arizona from requiring a Federal Form applicant to submit information beyond hat required by the form itself,” Scalia wrote for the court.

Progressive legal advocates had warned that the Arizona law would place undue burdens on minority groups. They hailed the decision as a victory for voting rights.

“Voters scored a huge victory today,” said Wendy Weiser, the director of New York University’s Brennan Center for Justice. “We applaud the Supreme Court for confirming Congress’s power to protect the right to vote in federal elections.”

Arizona’s Proposition 200 was adopted by the voters in 2004. Copycat laws in three other states — Alabama, Georgia and Kansas — may also be in trouble. The three states supported Arizona’s argument that the NVRA form is insufficient to guard against voter fraud.

“Today’s decision means that these laws are preempted by the National Voter Registration Act,” said David Gans, the civil rights director of the Constitutional Accountability Center, a liberal law group. He noted that Alabama’s brief argued that its voter law and laws in other states were “verbatim replicas” of the Arizona statute.

“Under Justice Scalia’s analysis, these copycat provisions are inconsistent with Congress’ efforts, using its Elections Clause authority, to streamline the registration process and prevent states from denying citizens the right to register to vote in federal elections,” Gans argued. “I think we can expect to see voters in these other states using today’s opinion to strike down these replicas of the Arizona law struck down today.”

During oral arguments back in March, Scalia wondered aloud why Arizona didn’t challenge the NVRA directly. A silver lining for proponents of proof-of-citizenship laws is that his majority opinion noted that the state is free to challenge the broader requirement that states accept the federal voter registration form.

“Arizona may, however, request anew that the [Election Assistance Commission] include such a requirement among the Federal Form’s state-specific instructions, and may seek judicial review of the EAC’s decision under the Administrative Procedure Act,” he wrote.

Alito argued in his dissent that Congress was less than clear about what the NVRA requires, concluding that the relevant portions of the law hold that “the States need not treat the federal form as a complete voter registration application.”