Arizona and Kansas have taken Supreme Court Justice Antonin Scalia’s suggestion and sued the Obama administration in a continuing effort by both states to require proof of citizenship in order to register to vote. The lawsuit, filed Wednesday, was announced by Arizona’s Attorney General Tom Horne and Secretary of State Ken Bennett, and joined by Kansas Secretary of State Kris Kobach, a high-profile architect of restrictionist laws, including Arizona’s Senate Bill 1070. The issue involves the 1993 National Voter Registration Act, also known as the “motor voter” law, which requires states to let people register to vote simply by attesting they are citizens, when renewing their driver’s license or applying for social services. A 2004 law adopted by the voters in Arizona added the requirement that people registering to vote also provide proof of citizenship. The Supreme Court struck down that law earlier this year, concluding that it is trumped by the motor voter law. Arizona, the court ruled, could not add new requirements to the form prescribed by the federal law. But during oral arguments in March, Scalia expressed his bafflement that Arizona did not launch a broader assault on the constitutionality of the NVRA form, written by the Election Assistance Commission. The state simply contended in that case that its proof of citizenship law did not violate the federal law. Even Scalia disagreed with that, voting against Arizona in the ruling, but also giving them a valuable tip in his 7-2 majority opinion.