One of the biggest mysteries that has emerged from the Trump-era Supreme Court is the 2023 decision in Allen v. Milligan.

In Milligan, two of the Republican justices — Chief Justice John Roberts and Justice Brett Kavanaugh — voted with the Court’s Democratic minority to strike down Alabama’s racially gerrymandered congressional maps, ordering the state to redraw those maps to include an additional district with a Black majority.

As Roberts emphasized in his opinion for the Court in Milligan, a lower court that also struck down these maps “faithfully applied our precedents.” But the Roberts Court frequently overrules or ignores precedents that interpret the Voting Rights Act — the federal law at issue in Milligan — to do more than block the most egregious forms of Jim Crow-like voter suppression. And the Court’s Republican majority is normally hostile to lawsuits challenging gerrymanders of any kind.

Most notably, in Rucho v. Common Cause (2019), the Republican justices held that federal courts may not hear suits challenging partisan gerrymanders. Among other things, Rucho enables tactics like Texas Republicans’ current plans to redraw that state’s congressional maps to maximize GOP power in Congress.

So why did two Republican justices break with their previous skepticism of gerrymandering suits in the Milligan case? A new order that the Supreme Court handed down Friday evening appears to answer that question.

The new order, in a case known as Louisiana v. Callais, suggests that the Court’s decision in Milligan was merely a minor detour, and that Roberts and Kavanaugh’s votes in Milligan were largely driven by unwise legal decisions by Alabama’s lawyers. The legal issues in the Callais case are virtually identical to the ones presented in Milligan, but the Court’s new order indicates it is likely to use Callais to strike down the Voting Rights Act’s safeguards against gerrymandering altogether.

The Callais order, in other words, doesn’t simply suggest that Milligan was a one-off decision that is unlikely to be repeated. It also suggests that the Court’s Republican majority will resume its laissez-faire approach to gerrymandering, just as the redistricting wars appear to be heating up.

A brief history of the Supreme Court’s approach to gerrymandering

Broadly speaking, there are two kinds of lawsuits alleging that a legislative map is illegally gerrymandered. Partisan gerrymandering suits claim that a map was drawn to maximize one major political party’s power at the expense of the other. Racial gerrymandering suits, meanwhile, allege that a state’s legislative maps improperly dilute the voting power of voters of a particular race.

Prior to Rucho, the Court imposed minimal — but not entirely nonexistent — limits on partisan gerrymandering. It has historically been more aggressive in policing racial gerrymanders.

The Supreme Court held in Davis v. Bandemer (1986) that federal courts may hear claims alleging that a state’s maps are so egregiously partisan that they amount to unconstitutional discrimination. The idea is that maps that intentionally inflate Democratic voters’ power, while minimizing Republican voters’ power (or vice-versa) violate the Constitution’s guarantee that all voters should have an equal say in elections.

Notably, however, no five justices agreed to a single legal standard that would allow courts to determine which maps are illegal partisan gerrymanders in Davis. Nor did a majority of the Court set such a standard in later lawsuits challenging partisan gerrymanders. In Rucho, the Republican justices essentially announced that the Court would give up its quest to find such a standard. A few years later, in Alexander v. NAACP (2024), those justices went even further, declaring that “as far as the Federal Constitution is concerned, a legislature may pursue partisan ends when it engages in redistricting.”

Though Davis’s limits on partisan gerrymandering were always fuzzy, it is likely that this ambiguity deterred at least some states from enacting extreme gerrymanders that might have caused the courts to intervene. At the very least, Rucho changed how states litigate gerrymandering suits. Before Rucho, states accused of gerrymandering would often try to offer another explanation for why their maps benefited one party or the other. Now, they will openly state in their briefs that they drew maps for partisan reasons — confident that federal judges will do nothing, despite these confessions.

Historically, however, the Court has imposed more concrete limits on racial gerrymanders. In Milligan, for example, the Court struck down Alabama congressional maps that would have given Black voters a majority in just one of the state’s seven districts (or 14 percent of the districts), despite the fact that Black people make up about 27 percent of the state’s population. The Court ordered the state to draw new maps with two Black-majority districts.

The linchpin of Milligan and similar cases is the Court’s decision in Thornburg v. Gingles (1986), which laid out the rules governing when an alleged racial gerrymander violates the Voting Rights Act (which broadly prohibits race discrimination in elections). The framework laid out in Gingles is notoriously complicated, but it turns on whether voters in a particular state vote in racially cohesive blocs.

Thus, for example, in a state where the white majority supports Republicans nearly all of the time, while the Black minority supports Democrats nearly all of the time, Gingles sometimes requires courts to redraw the state’s maps to ensure that the Black minority is adequately represented. This is because, in such a state, the white majority can wield its near-unanimous support for Republicans to cut Black voters (and Democrats) out of power altogether.

In a different state, where both Black and white voters sometimes vote for either party, Gingles tells courts to stay out of redistricting. Black voters, after all, are United States citizens who have as much of a right to choose their leaders as anyone else. So, if they choose to be represented by a white Republican in a free and fair election, that’s their choice and the courts should honor it.

Because Gingles only kicks in when an electorate’s racial demographics closely match its partisan voting patterns, it places some practical limits on both partisan and racial gerrymandering. In Milligan, for example, Alabama was not able to draw maps that maximized Republican voting power because doing so required the state to dilute Black voting power. So, even though Rucho prevents lawsuits that challenge partisan gerrymandering directly, Gingles sometimes allows suits which target it indirectly by alleging that a partisan gerrymander is also an impermissible racial gerrymander.

But now the Court is signaling that it is likely to overrule Gingles and abolish suits alleging that racial gerrymanders violate the Voting Rights Act altogether.

So what’s the deal with the Court’s new order in Callais?

The Callais case is virtually identical to Milligan — indeed, the cases are so similar that Louisiana said in a brief to the justices that Callais “presents the same question” as the Alabama redistricting case. Before the Callais case reached the justices, a lower court determined that Louisiana’s congressional maps violate Gingles, and ordered the state to draw an additional Black-majority district.

Nevertheless, when the Supreme Court heard oral arguments in Callais last March, all six of the Republican justices appeared to disagree with this lower court’s decision — although the lower court’s decision merely applied the same legal rules that the Supreme Court applied two years earlier in Milligan. Then, at the end of June, the Court issued a brief order announcing that it would hold an unusual second oral argument in Callais, and that it would seek additional briefing from the parties in this case.

On Friday, the Court issued a new order laying out what these parties should address in those briefs. Those briefs should examine whether the lower court order requiring Louisiana to draw an additional Black-majority district “violates the Fourteenth or Fifteenth Amendments to the U.S. Constitution.” The justices, in other words, want briefing on whether Gingles — and the Voting Rights Act’s safeguards against racial gerrymandering more broadly — are unconstitutional.

This suggestion that the Voting Rights Act may be unconstitutional — or, at least, that it violates the Republican justices’ vision of the Constitution — should not surprise anyone who has followed the Court’s voting rights cases.

In Shelby County v. Holder (2013), the Republican justices neutralized a different provision of the Voting Rights Act, which required states with a history of racist election practices to “preclear” new election laws with federal officials before they take effect. The Court’s Republican majority labeled this provision “strong medicine” that could be justified to combat the kind of widespread racial voting discrimination that existed during Jim Crow. But they argued that the United States was not racist enough in 2013 to justify letting preclearance remain in place.

“There is no denying,” Roberts wrote for the Court in Shelby County, “that the conditions that originally justified these measures no longer characterize voting in the covered jurisdictions.”

Although Kavanaugh joined nearly all of the majority opinion in Milligan, he also wrote a separate opinion indicating that he wanted to extend Shelby County to gerrymandering cases in a future ruling. “Even if Congress in 1982 could constitutionally authorize race-based redistricting under [the Voting Rights Act] for some period of time,” Kavanaugh wrote, “the authority to conduct race-based redistricting cannot extend indefinitely into the future.”

Gingles also suggests that Voting Rights Act suits challenging racial gerrymanders should eventually cease to exist. If the electorate ceases to be racially polarized — something that appears to be slowly happening — then Gingles plaintiffs will no longer be able to win cases, and the federal judiciary’s role in redistricting will diminish. But Kavanaugh seems to be impatient to end these suits while many states remain racially polarized.

Read in the context of Kavanaugh’s Milligan opinion, in other words, the new Callais order suggests that a majority of the justices have decided the Voting Rights Act’s safeguards against racial gerrymandering have reached their expiration date, and they are looking for arguments to justify striking them down.

It now looks like Milligan was Gingles’s last gasp. The Republican justices remain hostile both to the Voting Rights Act and toward gerrymandering suits more broadly. And they appear very likely to use Callais to remove one of the few remaining safeguards against gerrymanders.