In 2010, Republicans gained control of the Alabama legislature for the first time in 136 years. The redistricting maps drawn by Republicans following the 2010 election preserved the thirty-five majority-minority districts in the Alabama legislature—represented overwhelmingly by black Democrats—and in some cases actually increased the number of minority voters in those districts.

For example, State Senator Quinton Ross, a black Democrat elected in 2002, represented a district in Montgomery that was 72 percent African-American before the redistricting process. His district was under-populated by 16,000 people, so the Alabama legislature moved 14,806 African-Americans and thirty-six whites into his seat. The new district was now over 75 percent black and excluded white neighborhoods that were previously in Ross’s district.

Republicans claimed they were merely complying with the Voting Rights Act. Black Democrats challenged the redistricting maps as an unconstitutional racial gerrymander and took the case to the Supreme Court. Today the Court, in a 5-4 decision written by Justice Breyer, sided with the black plaintiffs and ordered a district court in Alabama to reexamine whether specific districts, like Ross’s, were improperly drawn with race as the predominant factor. The decision was released, interestingly enough, on the same day as the fiftieth anniversary of the march from Selma to Montgomery.

“The record indicates that plaintiffs’ evidence and arguments embody the claim that individual majority-minority districts were racially gerrymandered, and those are the districts that the District Court must reconsider,” Breyer wrote. Section 5 of the Voting Rights Act (which the Supreme Court gutted in 2013, in another case from Alabama) did not compel the legislature to preserve the exact number of minority voters in a given district or inflate those numbers. “Section 5 does not require a covered jurisdiction to maintain a particular numerical minority percentage. It requires the jurisdiction to maintain a minority’s ability to elect a preferred candidate of choice,” Breyer said. The court’s majority—joined by Justice Kennedy—sympathized with the plaintiffs’ claim that Alabama’s interpretation of the VRA may “harm the very minority voters that Acts such as the Voting Rights Act sought to help.”

Justices Scalia and Thomas dissented. “We have somehow arrived at a place where the parties agree that Alabama’s legislative districts should be fine-tuned to achieve some ‘optimal’ result with respect to black voting power; the only disagreement is about what percentage of blacks should be placed in those optimized districts. This is nothing more than a fight over the ‘best’ racial quota,” wrote Thomas.

The ruling could have important ramifications, since the strategy followed by Alabama Republicans—packing minority voters into heavily Democratic seats in order to weaken white Democrats—was replicated throughout the South after the 2010 elections. I wrote about this trend in a 2012 feature for The Nation, “How the GOP Is Resegregating the South”:

In virtually every state in the South, at the Congressional and state level, Republicans—to protect and expand their gains in 2010—have increased the number of minority voters in majority-minority districts represented overwhelmingly by black Democrats while diluting the minority vote in swing or crossover districts held by white Democrats. “What’s uniform across the South is that Republicans are using race as a central basis in drawing districts for partisan advantage,” says Anita Earls, a prominent civil rights lawyer and executive director of the Durham-based Southern Coalition for Social Justice. “The bigger picture is to ultimately make the Democratic Party in the South be represented only by people of color.”

White Democrats have become the biggest casualty of the GOP’s new Southern strategy. As Jason Zengerle wrote in The New Republic, “Prior to the 2010 election, the Alabama House had sixty Democratic members, 34 of them white and 26 black. Afterward, there were 36 Democrats—ten white, 26 black. Meanwhile, in the Alabama Senate, the number of black Democrats remained seven, while the number of white Democrats fell from 13 to four.” After the 2014 election, there are now only seven white Democrats in the Alabama legislature—one in the Senate and six in the House.

There are no longer any white Democrats from the Deep South in Congress, following the defeat of Georgia Congressman John Barrow in 2014. Georgia Republicans moved 41,000 black Democrats out of his Savannah-based district to make him more vulnerable to a Republican challenge.

The elimination of white Democrats has also crippled the political aspirations of black Democrats. For years, black Democrats served in the majority with white Democrats in state legislatures across the South. Today Republicans control every legislative body in the South except for the Kentucky House. Before the 1994 elections, 99.5 percent of black Democrats served in the majority in Southern state legislatures. After the 2010 election, that number dropped to 4.8 percent, according to the Joint Center for Political and Economic Studies. “Black voters and elected officials have less influence now than at any time since the civil rights era,” the report found.

In the 1990s, some black Democrats formed an “unholy alliance” with white Republicans to create new majority-minority districts in the South. Republicans supported these districts for black Democrats in select urban and rural areas in exchange for an increased GOP presence elsewhere, especially in fast-growing metropolitan suburbs. With Democrats grouped in fewer areas, Republicans found it easier to target white Democrats for extinction.

But that unholy alliance ended after 2010, when black Democrats across the South, like Georgia Senate minority leader Stacey Abrams, denounced the GOP’s redistricting strategy. They found it especially ironic that Republicans were using the VRA as a rationale for marginalizing black voters while at the same time pushing the Supreme Court to gut the most important part of the VRA—the requirement that states with the worst history of voting discrimination, like Alabama, clear their voting changes with the federal government.

Even though Southern states like Alabama no longer have to have their redistricting maps approved by the federal government, the Court’s decision today could open the door for additional challenges to GOP-drawn racial gerrymanders in states like Virginia and North Carolina. “Today’s Alabama decision gives these challengers a new tool, making it harder for states to use compliance with the Voting Rights Act as a pretext to secure partisan advantage,” writes Rick Hasen.

It’s a modest victory, but perhaps the best that can be expected from the current Supreme Court.