The Supreme Court handed down one voting rights ruling on Monday, and left another for a later day. Both cases are, in a way, reflective of how American attitudes about race are changing. Monday's ruling, on the National Voter Registration Act, is about how the West is rapidly changing as the Latino population booms. The more consequential case on the Voting Rights Act's Section 5 is about whether the South has changed enough in the last 50 years.

The National Voter Registration Act was passed in 1993, and required state governments to let people register to vote at the same time they got their driver's licenses. In Arizona v. Inter Tribal Council, Arizona required additional proof of citizenship to register to vote beyond what the federal form requires. With the growth of its Latino population — up 46 percent in the last 10 years — the state has enacted controversial immigration laws, like the one requiring police to demand the citizenship papers of anyone they have reason to believe might be an illegal immigrant. In a 7-to-2 decision, the Supreme Court struck down Arizona's voter registration requirements, finding that its law was preempted by the NVRA.

The Voting Rights Act case is much, much bigger. In Shelby County v. Holder, an Alabama county is suing over the VRA Section 5, which requires that certain voting districts that have a history of racial discrimination must pre-clear any changes to their voting rules with the Department of Justice. Shelby County says the law — which costs time and money to comply with — doesn't apply to every place equally, exceeds Congress's authority under the Fourteenth and Fifteenth Amendments and therefore violated the Tenth Amendment and Article IV of the Constitution. Since 1982, DoJ has blocked 2,400 proposed changes to voting laws — including in 2012, in Texas and South Carolina. Has the South changed enough since 1965 Section 5 is no longer necessary? Many have argued yes. In 2009, Chief Justice John Roberts seemed to think so, writing, "We are now a very different nation." During oral arguments in February, Roberts asked whether  the government believed "that the citizens in the South are more racist than citizens in the North." Project of Fair Representation director Edward Blum, who worked on Shelby County's lawsuit, said last fall, "The America that elected and re-elected Barack Obama as its first African American president is far different than when the Voting Rights Act was first enacted in 1965. Congress unwisely reauthorized a bill that is stuck in a Jim Crow-era time warp. It is unconstitutional."

But many places covered by Section 5 did not vote for Obama. State and county redistricting matters less for national elections than for local ones. And we have some evidence that, while horrible Jim Crow laws are no longer in effect, racial bias is still significant in the South. Take, for example, this New York Times map showing the counties that voted more Republican in 2008 than they did in 2004. The 2008 election was a landslide for the Democratic candidate, as the Republican in the White House, George W. Bush, had grown unpopular because of the wars, the fiscal crisis, and other scandals. But many places in the South bucked the national trend. We don't know if that's because the Democratic candidate was black, but the geographic pattern is hard to ignore. During oral arguments on the VRA case, Justice Sonia Sotomayor noted that Shelby County has had more than 200 voting rules changes blocked by the Justice Department. Even if the South has changed, Sotomayor told the lawyer for Shelby County, "your county pretty much hasn't." But according to SCOTUSblog, Sotomayor might be in the minority with that view, as swing vote Justice Anthony Kennedy seemed unlikely to uphold the law. We could see a decision as soon as Thursday.