A federal judge has nullified a New Hampshire law that restricted new voters from using a sworn affidavit to prove their citizenship in the absence of official documentation like a birth certificate or passport.

Judge Samantha D. Elliott of the U.S. District Court in New Hampshire issued the decision, declaring that the removal of affidavits as proof of citizenship posed an unjustifiable burden on the right to vote, violating the First and 14th Amendments. Passed in 2024 and signed by then-Governor Chris Sununu, the law was annulled immediately by the ruling.

New Hampshire’s Justice Department plans to appeal the decision. State spokesman Michael Garrity defended the regulation, describing it as a sensible measure designed to safeguard electoral integrity.

The legislation was among the nation’s strictest voter registration laws and faced legal challenges from the American Civil Liberties Union of New Hampshire. The League of Women Voters of New Hampshire supported this challenge.

Henry Klementowicz, the A.C.L.U.’s deputy legal director, emphasized New Hampshire’s history of secure elections, arguing that the law could have unnecessarily barred thousands of eligible voters from participating in elections.

Judge Elliott also noted that reports of wrongful voting did not decrease with the law’s enactment. The number of such reports filed with the state attorney general remained similar in the years before and after the law’s passage.