The Biden administration sued Arizona on Tuesday to block a new law requiring proof of citizenship in order to vote in federal elections.

Calling it a "textbook violation of the National Voter Registration Act," Assistant Attorney General Kristen Clarke of the Justice Department's Civil Rights Division said that the law's requirement was "onerous" - and took particular issue with provisions such as "requiring election officials to reject voter registration forms based on errors or omissions that are not material to establishing a voter's eligibility to cast a ballot."

The new law would require voters to prove citizenship using documentation such as a driver's license, passport, birth certificate or naturalization papers.