The Supreme Court will decide the constitutionality of a stringent Arizona voter registration law. (AP Photo/Pablo Martinez Monsivais.)

Three weeks after hearing a challenge to the heart of the Voting Rights Act, the Supreme Court will decide another important voting rights case following oral arguments today in Arizona v. The Inter Tribal Council of Arizona.

In 2004, Arizona voters approved Proposition 200, a stringent anti-immigration law that included provisions requiring proof of citizenship to register to vote and government-issued photo ID to cast a ballot. Last year, the US Court of Appeals for the Ninth Circuit blocked the proof of citizenship requirement, which it said violated the 1993 National Voter Registration Act (NVRA). Under the NVRA, those using a federal form to register to vote must affirm, under penalty of perjury, that they are US citizens. Twenty-eight million people used that federal form to register to vote in 2008. Arizona’s law, the court concluded, violated the NVRA by requiring additional documentation, such as a driver’s license, birth certificate, passport or tribal forms. According to a 2006 study by the Brennan Center for Justice, at least 7 percent of eligible voters “do not have ready access to the documents needed to prove citizenship.”

Prop 200 has had a chilling effect on voter registration in Arizona. “Following enactment of Proposition 200, over 31,000 individuals were rejected for voter registration in Arizona,” according to a brief by the Mexican American Legal Defense Fund (MALDEF). “Less than one-third of the rejected registrants subsequently successfully registered to vote.” The law has needlessly prevented eligible voters from registering and has made voter registration work more difficult. “The proportion of all voter registrations in [Phoenix’s] Maricopa County attributable to community-based drives decreased from 24% in 2004 to 7% in 2005, 5% in 2006 and 6% in 2007,” found MALDEF.

Prop 200 was aimed at curtailing illegal immigration but has harmed many legal Arizonians. Of the 31,500 citizens who were prevented from registering to vote, MALDEF found, “the record in the case demonstrates that the rejected…registrants were Democrats and Republicans in equal numbers, almost one-half were under the age of 30, and a majority of those who indicated a race said they were white.”

Supporters of Prop 200 claim the proof of citizenship requirement is needed to stop voter registration fraud. But as the appeals court found, “Arizona has not provided persuasive evidence that voter fraud in registration procedures is a significant problem in Arizona; moreover, the NVRA includes safeguards addressing voter fraud.” Adds Nina Perales, vice president of litigation at MALDEF: “Nobody has ever been prosecuted for using the federal form to register to vote as a non-citizen.” There have been only seven cases of alleged election fraud in Arizona since 2000, according to an exhaustive study by News21, and the two alleged instances of non-citizens voting were dismissed.

Nonetheless, Arizona’s Prop 200 has served as a model for other states looking to pass new voting restrictions. (The conservative lobbying group ALEC recommended the bill to state legislatures in 2008.) Three states—Alabama, Kansas and Tennessee—adopted proof of citizenship laws for voter registration since the 2010 election and legislation was introduced in nine other states (Colorado, Connecticut, Maine, Massachusetts, New Hampshire, Nevada, Oregon, South Carolina and Texas.) Kansas Secretary of State Kris Kobach claimed in 2011 that sixty-seven non-citizens had illegally registered, out of 1.7 million on the state’s voter rolls, but “was unable to identify a single instance of a non-citizen illegally casting a vote, or any successful prosecution for voter fraud in the state,” according to the Brennan Center. Why would a non-citizen, who presumably is in the United States to work, risk deportation and imprisonment in order to cast a ballot? Kobach once suggested in a radio interview that perhaps their coyote was paying them to vote, which defies all logic.

More likely, proof of citizenship laws are a way for opponents of increased minority participation in the electoral process to forestall the impact of demographic change, particularly in states like Arizona with a fast-growing Hispanic population. “Is some of the motivation behind this law to slow down the growth of the electorate?” asks Perales. “I believe so.”

In hearing the Arizona case, the Supreme Court will once again decide what powers Congress has to protect the right to vote. In the recent challenge to the Voting Rights Act, the Court’s conservative majority seemed skeptical of the steps Congress could take the remedy past and present voting discrimination. Will they take a similarly dim view of Congressional authority again? The appeals court found that the Elections Clause of the Constitution—Article I, Section 4—gives Congress the ability to regulate federal elections, contrary to Arizona’s submission. The Supreme Court has recognized this repeatedly, most recently in the 1997 case Foster v. Love. “The Constitution gives Congress the ultimate authority in setting rules for federal elections,” says Perales. Unless, of course, the justices maintain that registering to vote, like the Voting Rights Act, is just another racial entitlement.

UPDATE: The lawyers opposing Prop 200 seemed pleased with how the oral arguments proceeded. “Based on the discussion in the courtroom this morning, we are confident,” said Nina Perales. “The argument, from our perspective, went well,” said Jon Greenbaum of the Lawyers’ Committee for Civil Rights.

Justice Scalia, perhaps not surprisingly, led the charge in defense of Prop 200, while Justice Sotomayor said the law clearly violated the NVRA. “Some of us do believe in legislative history,” said Sotomayor. “Some of my colleagues don’t.” In response, Scalia pointed at himself.

Justice Kennedy, the court’s swing vote, “seemed to advocate for both sides of the case,” reported Ryan Reilly of The Huffington Post.

Kennedy argued that the federal form “is not worth very much” if Arizona could simply impose additional requirements on top of it, but later said that states had a “vital interest” in federal elections.

As Congress was honoring Rosa Parks late last month, conservative Supreme Court justices were discussing a change to the Voting Rights Act that could undo many civil rights successes.