The U.S. Supreme Court heard arguments today in a voting rights case which experts say may have a profound effect on how far states can go to impede the federally-protected right to vote.
At issue in Arizona v. The Inter Tribal Council of Arizona  is the viability of that state’s Proposition 200, approved by voters in 2004. Prop 200 requires people registering under the federal National Voter Registration Act — the 1993 “motor voter” law which permits registration when applying for a driver’s license or for social services — to do more than attest to their citizenship on the federal form; they must produce proof of that citizenship.
Some 30,000 likely-eligible voters, many of whom were Latinos, were initially blocked  from registration during the 20 months following the passage of Prop 200, according to the Associated Press.
Challengers say Prop 200 inappropriately trumps the motor-voter law by requiring potential voters to do more than is required under the federal law.
“If Arizona’s brazen attempt to evade the mandates of the NVRA is upheld, it will make it tougher for voters in Arizona to register, and other states with legislatures that are looking to suppress the vote will surely try to pass copycat legislation,” said Doug Kendall , the president of the Constitutional Accountability Center. “If the Court accepts Arizona’s most sweeping arguments against the NVRA, its ruling could severely limit Congress’ power to protect the right of Americans to register to vote.”
But the law’s proponents contend that Arizona was within its rights to define voter qualifications.
Reports  from today’s argument reveal a court closely-divided along expected lines, with Justices Sonia Sotomayor and Antonin Scalia taking the lead on opposing sides.
Sotomayor, firing off a series of questions at Arizona Attorney General Thomas C. Horne, said that she had a “real disconnect” with Prop 200. Justice Elena Kagan followed along, saying that Prop 200 “essentially creates new requirements, and a new form.”
But Scalia countered that the federal form didn’t do enough to confirm eligibility: “So it’s under oath — big deal,” he said. He added that both state and federal requirements could exist side-by-side, a point with which Justice Samuel Alito  agreed.
But Justice Anthony Kennedy, who could be the swing vote according to Scotusblog’s Lyle Denniston , showed some skepticism about the state’s power to add complicating requirements to the federal registration system.