It may not be what you think.
In its 5-4 decision along partisan lines, the conservative majority tossed out the Act's insistence that nine mostly Southern states and a few other cities and counties with a history of racial discrimination must get pre-clearance from the federal government before changing their voting laws.
Justice Roberts, writing for the majority, called the relevant section "unconstitutional" and the calculus outdated.
But what's really unconstitutional is the way that many Republican-dominated states are already raising barriers to voting, barriers that are aimed at African Americans, other minorities, and other groups that vote disproportionately Democratic.
The Brennan Center for Justice called these schemes "the biggest rollback in voting rights since the Jim Crow era," as Kevin Alexander Gray noted in an insightful article about the Voting Rights court case earlier this year.
We've been seeing one Republican state after another pass Voter ID laws, even though voter fraud is already illegal and practically nonexistent. Minorities, the elderly, and students are the people least likely to have the ID on hand.
We've seen Republican legislatures try to get rid of same-day voting, or limit absentee voting or early voting.
We've seen Republican legislatures gerrymander one district after another to dilute the representation of African Americans.
These legislatures -- some of them in states that used to be, until today, covered by the Voting Rights Act pre-clearance requirement -- are doing everything in their power to shrink the franchise. And now the Supreme Court has just given all of them a green light to disenfranchise.
The result will be fewer Democratic votes, for sure.
But much, much more seriously, the result will be an impairment of our democracy -- and once again a racist one.
If you liked this story by Matthew Rothschild, the editor of The Progressive magazine, check out his story Sanders Introduces Bill to Curb Domestic Spying.
Follow Matthew Rothschild @mattrothschild on Twitter.