Volunteers hold up a banner at the start of a voter registration rally in Phoenix. Ariz. voter ID law overturned

A six-year-old Arizona law requiring that voters prove their citizenship in order to register to vote was struck down Tuesday.

The 9th U.S. Circuit Court of Appeals upheld the portion of the law requiring that voters present identification before casting their ballot, part of a proposition passed in 2004 amid concerns that illegal immigrants may try to vote in state and federal elections.


Opponents of the law argued that it would lead to thousands of residents being turned away at their polling places.

The 2004 ballot proposition required that those registering to vote produce documentation proving citizenship — such as a passport — to register to vote. To cast a ballot, registered voters needed to produce either one form of photo identification or two forms of identification without a photo.

The 9th Circuit panel found that the proof of citizenship in order to register conflicted with federal voter registration law.