Critics of Section 5 see these findings as evidence that the stubborn problem that made Section 5 necessary—minorities being denied access to the polls—has largely been solved, and that the extraordinary federal interference in state affairs is no longer justified.

For a state-by-state breakdown of voter turnout and factors such wait times at polling stations, check out the Pew Election Performance Index .

-Racial attitudes and socio-economic gaps. As part of the current Supreme Court case, a half dozen law and political science professors from universities across the country have submitted a brief comparing recent socio-economic and voting data from regions covered by Section 5 with data from uncovered jurisdictions. Among other things, they found that (1) “negative racial attitudes are more prevalent in covered jurisdictions”; (2) “covered jurisdictions are more likely to adopt vote denial and suppression measures”; and (3) “non-white voters in covered jurisdiction are vulnerable due to socioeconomic disparities.” The document is packed with useful statistics and analysis.

-The Section 2 litmus test. Besides Section 5, the Voting Rights Act includes another safeguard, known as Section 2, which allows minorities and their advocates to challenge discriminatory voting practices by bringing suit after the fact. And, unlike Section 5, it applies everywhere in the country.

Morgan Kousser, a professor of history and social science at the California Institute of Technology, has spent the last four years compiling data on voting rights incidents, including Section 2 cases. While these can be brought anywhere, he’s found that more than 83 percent of successful Section 2 suits arose in jurisdictions that were also covered by Section 5. Ellen Katz of the University of Michigan has unearthed a similar pattern.

Both researchers see these findings as evidence that (contrary to the claims of Section 5’s critics) discriminatory voting practices remain more prevalent in covered jurisdiction than in other parts of the country.

As Kousser wrote in a recent Voting Rights Act series, which ran on Reuters’s blog, The Great Debate, “five-sixths or more of the cases of proven election discrimination from 1957 through 2013 have taken place in jurisdictions subject to Section 5 oversight,” a finding he believes justifies Section 5’s continued existence.

Katz takes the argument a step further, noting that electoral changes in covered regions undergo Justice Department vetting—a system that filters out provisions that would harm minorities and leads to self-policing. “Given these blocking and deterrent effects,” Katz wrote in recent Voting Rights Act symposium on SCOTUSblog, “we should expect to find fewer instances of discriminatory practices in places subject to Section 5 if, as critics of the VRA contend, places like Alabama are truly no different from places like Ohio.” In Katz’s view, the fact there are more instances rather than fewer is a particularly strong sign that voting discrimination is more pervasive in covered regions.
Both the Reuters series, which is curated by Rick Hasen, an election-law guru, and the SCOTUSblog symposium, offer a variety of expert perspectives on the Supreme Court case.

-The self-policing effect. Not surprisingly, the fact that the Justice Department vets voting-system changes has led lawmakers in jurisdictions covered by Section 5 to craft electoral measures with the Voting Rights Act in mind. This can make it tough to gauge just how much impact Section 5 has had since haggling over things like legislative language usually happen behind close doors.

There are, however, some telling exceptions. In 2011, South Carolina passed an ultra-strict voter ID law. The Justice Department found “significant racial disparities” in the way the law would affect voter access, and referred it to the courts for further review. State legislators responded by voluntarily softening the provisions—in particular, they made it easier for people with a “reasonable impediment” to vote without a picture ID.

Last year, a three-judge panel at the District Court in Washington, DC unanimously approved the revised law, saying it “accomplishes South Carolina’s important objectives while protecting every individual’s right to vote.” In a separate concurring opinion , Judge John D. Bates—a George W. Bush appointee—noted that the process showed the “vital function of Section 5” in thwarting “problematic” voting changes. (You can find more information about the South Carolina case on the website of the Brennan Center for Justice.)

Mariah Blake writes for the United States Project, CJR's politics and policy desk. She is based in Washington, DC, and her work has appeared in The Atlantic, The New Republic, Foreign Policy, Salon, The Washington Monthly, and CJR, among other publications.