by Spencer Overton, a Professor of Law at The George Washington University Law School and a Senior Fellow at Demos.This piece is crossposted at The Huffington Post.
I attended yesterday’s U.S. Supreme Court oral argument in the Arizona voter registration case. The argument went well generally, but Justice Alito suggested the Justices would create a “crazy” double standard by requiring that Arizona election officials accept the federal registration form. 
Alito’s concerns are unwarranted. Arizona chose to create two standards when it chose to add special “proof of citizenship” to register.
The National Voter Registration Act requires that all states “accept and use” a single, uniform voter registration form for federal elections (states can also still use their own registration forms).
The Federal Form requires that prospective voters check a box and sign an affirmation that they are U.S. citizens under penalty of perjury.
Arizona, however, adopted a state law requiring “satisfactory proof” of U.S. citizenship to register, such as a birth certificate, U.S. passport, or state driver’s license that shows citizenship. As a result, Arizona rejected over 31,000 registrations that lacked its “proof of citizenship” -- including Federal Forms -- even though Arizona concedes it has no evidence that any of these individuals were non-citizens.
My take is that Arizona must accept all Federal Forms that comply with the citizenship affirmation rules set by Congress. The federal Act was designed to expand participation in federal elections by streamlining the registration process with a simple, uniform Federal Form that prevents states from piling on additional hurdles to register. Indeed, as Justice Sotomayor mentioned, Congress explicitly rejected an amendment that would have allowed states to require “documentary evidence” of U.S. citizenship.
rizona’s rigid anti-immigrant law, some pundits scored 
easingly has difficulty, as The Washington Post’s Dana Milbank