Here's an article on slate.com summarizing the arguments, from both the principle parties and the justicies, in the most recent challenge to protecting minority voting rights. Here's a NY Times op-ed explaining things.
When Congress passed the Voting Rights Act in 1965, they wrote Section 5 of the act which singled out Southern states for special federal oversight. Now, conservatives, including the conservative justices, are arguing that it should maybe overturned for unfairly attacking states' rights. Even though Congress just recently reauthorized Section 5 in 2006, and according to conservatives it's not the job of judges to "legislate from the bench," if proponents of voting rights can't sway Justice Kennedy to their perspective, Section 5 just might be overturned. What makes Section 5 particularly insulting to Dixie is that there're are northern states who track much worse than they do. (I have to add here that that's an odd, historical argument - that Dixie should not be judged because there are places in the north that are much more virulently racist.) At least, that's how I understand it.
I have a suggestion. Why not place all 50 states under Section 5?