US Supreme Court: Arizona Citizenship Proof Law Illegal

States can't require voters to prove they are U.S. citizens before they can use a federal voter registration system designed to make it easier to sign up.

That ruling comes today from the Supreme Court. It involves a requirement that was approved by Arizona voters. But four other states -- Alabama, Georgia, Kansas and Tennessee -- have similar requirements. And 12 other states are considering that type of legislation.

By a vote of 7-2, the justices rejected the law forcing Arizona voters to document their citizenship in order to use the registration form produced under the federal "Motor Voter'' law.

An official with a Mexican-American advocacy group says the ruling means that states can't impose "burdensome paperwork requirements'' on top of what federal law requires in order to vote.

Arizona officials, though, have argued that they should be able to pass laws to stop illegal immigrants and other non-citizens from getting on their voting rolls.

And Justice Clarence Thomas, writing the dissenting opinion, said states are allowed to determine the qualifications of voters in federal elections, which means they can determine whether voters meet those qualifications.