The Citizen Ballot Protection Act would amend federal voter registration law to allow states to require proof of citizenship from people registering to vote by mail. Currently, the National Voter Registration Act of 1993 sets uniform standards for mail-in voter registration forms, and this bill would give states the option to add citizenship documentation requirements beyond those existing standards. The change applies to both federal elections and, according to the bill's language, other elections as well. The bill takes effect immediately upon passage and requires no specific funding. The legislation was introduced in November 2025 by a group of Republican senators and would ultimately affect any citizen attempting to register to vote by mail in states that choose to adopt the citizenship proof requirement.