Shelby County v. Holder, the case challenging the constitutionality of Section 5 of the Voting Rights Act, has gotten a lot of attention. But another very important voting rights case was argued on March 18 in the Supreme Court. This case, Arizona v. Inter-Tribal Council of Arizona, involves a challenge to Arizona’s requirement that people show proof of citizenship in order to register to vote. According to several accounts, Justice Sotomayor and Justice Scalia were both extremely active questioners in today’s arguments — and were clearly in disagreement. You can hear for yourself when the argument becomes available at the end of this week. Listen here or on your ISCOTUSnow app, available at the iPhone app store for free!