On April 17, 2012, the U.S. Court of Appeals for the Ninth Circuit (sitting in an 11-judge en banc panel) struck down a portion of Prop 200, an initiative adopted in November 2004 by Arizona voters for the purpose of preventing aliens from voting. The court upheld a provision requiring voters to show an ID on election day (such as a driver’s license) but struck down a provision requiring those seeking to register to vote to present documentary proof of citizenship. The decision was a partial setback for WLF, which filed a brief urging that Prop 200 be upheld. WLF argued that Arizona voters were within their rights in adopting measures designed to prevent election fraud. Although the court agreed with WLF that Prop 200 does not violate the Constitution, it held that the National Voting Rights Act of 1993 prohibits States from taking any steps to ensure that voting registrants are citizens, other than requiring registrants to state under oath that they are, indeed, citizens.