A prediction: If the Supreme Court strikes down part of the Voting Rights Act this term, we’ll read about Obama’s re-election—and especially the role played by black and Hispanic voters—in a majority opinion by Chief Justice John Roberts. After noting that the president’s giant share of support among minority voters pushed him over the top in key states, Roberts could point out that some Republicans started shifting ground on immigration the very next day.

The first lesson that just about everyone has drawn from the election: With the white vote shrinking, both parties have to court minority voters. If Republicans don’t figure out how to appeal broadly to Hispanics, in particular, they’ll eventually say goodbye even to their stronghold of Texas. There’s a second possible lesson from the 2012 results, however, which would be controversial indeed in the hands of Roberts and the conservative wing of the court: Given their electoral muscle, perhaps minority voters no longer need the protection of Section 5 of the Voting Rights Act.

My own answer to the riddle—and I’m in good company—comes down to timing. After one or two watershed elections, is it really the job of the court to tell Congress that it overstepped when it reaffirmed Section 5, by an overwhelming bipartisan vote, a mere six years ago? That’s the nut of the case before the court, a challenge to Section 5 brought by Shelby County, Ala. To begin cracking it, let’s start with a little Section 5 history.

Congress initially passed the Voting Rights Act in 1965 to deal with massive and violent suppression of black voters in the South. Remember Medgar Evans pushed out of his Mississippi polling place at gunpoint, and Freedom Summer in 1964, when hundreds of college students traveled to his state and others to register black voters? Three activists were killed that summer, many more were beaten, and dozens of black churches and businesses were wrecked and burned. And still, a year later only 6.7 percent of Mississippi’s eligible black voters were registered.

As New York University law professor Richard Pildes reminded me, part of the problem was that federal courts would strike down discriminatory measures like literacy tests, and Southern states and counties would quickly find ways to circumvent the court rulings. So in 1965, Congress gave the Voting Rights Act two sets of teeth. The first, Section 2, bans any voting practice that discriminates on the basis of race or ethnicity. It applies uniformly, throughout the country, and it has no expiration date. It’s enforced through lawsuits, with the burden of proof on the challenger, not the local or state government that has set up a new voting rule. The second part of the Voting Rights Act, Section 5, dealt directly with the problem of the recalcitrant South. Based on data showing a pattern of discrimination at the time, Congress created a category of “covered jurisdictions,” and said that for 25 years, any changes to voting rules in those places had to be cleared first by the Department of Justice, or approved in court, before they could go into effect. In these cases, the burden of proof is on the local and states governments to show that the changes they proposed won’t discriminate or dilute the power of minority votes. The list of covered jurisdictions includes most of the South, along with a smattering of counties and cities in other states.

In the decades since, a bunch of counties and cities have gotten themselves off the Section 5 list by showing that they’ve expanded voter participation and done their best to prevent intimidation and harassment. But when Congress last voted to reauthorize Section 5 in 2006, lawmakers left the law’s geographical scope intact. Pildes and other experts warned that this was a weird move, because there was no longer evidence that voting discrimination was an especial problem in all the Southern states that still have to go to the Department of Justice every time they want to change an election practice, and not a similar problem elsewhere. But Congress didn’t listen. And since then, the main study that supported the continuing relevance of Section 5, as written, has been effectively shredded. This is a problem the D.C. Circuit didn’t wrestle with in upholding Section 5 in the Shelby County case.

Read it at Slate.