The Supreme Court is on the brink of a conservative revolution, poised to roll back decades of progressive precedent and thrust itself into the 2020 presidential race. But as the term began on Monday, a majority of justices seemed poised to trigger an earthquake that could unsettle hundreds or even thousands of criminal convictions. The court appears prepared to rule that the Constitution require juries to reach unanimous verdicts in both state and federal court, abolishing a legal aberration that subordinates the power of minority jurors.

Louisiana and Oregon have long been the only two states that allow nonunanimous verdicts in felony trials. That means juries can reach a verdict by a vote of 10–2 or 11–1. In 2018, Louisiana voters eliminated nonunanimous verdicts moving forward, but individuals charged with a crime that occurred before 2019 can still be convicted by a divided jury. Oregon’s law remains in place despite a recent stab at reform.

Both Louisiana and Oregon’s nonunanimous jury rules are rooted in flagrant bigotry. In Louisiana, whites were infuriated by black citizens’ participation on juries during Reconstruction, believing that minorities would impede a just verdict. Racist lawmakers crafted a new state constitution that allowed for split verdicts, among other Jim Crow rules like a poll tax. Since almost every jury was predominantly white, this alteration ensured that a few black jurors would have little control over the outcome of a case. The law has worked as intended, as black jurors are disproportionately likely to be overruled by whites. Oregon introduced nonunanimous verdicts after a jury came one vote short of convicting a Jewish man of murder. This result triggered a wave of anti-Semitism and xenophobia that culminated in a state constitutional amendment approving split verdicts.

In a series of decisions dating back to the 19^th century, the Supreme Court has affirmed that the Sixth Amendment’s guarantee of a trial “by an impartial jury” in “all criminal prosecutions” requires unanimity. But the Sixth Amendment originally applied only to the federal government. The 14^th Amendment, ratified in the wake of the Civil War, “incorporated” much of the Bill of Rights against the states. Although the Supreme Court has incorporated the rest of the Sixth Amendment, it has never compelled states to follow the unanimous jury requirement. That leaves a curious anomaly in the law: If you are tried in federal court, the jury must reach a unanimous verdict; if you are tried in state court, the jury may convict you by a divided vote.

The anomaly persists for an extremely weird reason. In 1972’s Apodaca v. Oregon, five justices of the Supreme Court confirmed that federal juries must be unanimous. But one justice, Lewis Powell, wrote a bizarre concurring opinion declaring that state juries need not be, more or less on the basis of his own intuition. No other justice agreed, but Powell’s solo concurrence has been treated as binding precedent ever since.

Now Evangelisto Ramos—a Louisiana man convicted of second-degree murder in 2016 by a 10–2 vote—is challenging Powell’s rule. Ramos is backed up by a formidable array of states, racial justice advocates, progressives, and libertarians. They argue that it’s time for the Supreme Court to end the Apodaca anomaly and safeguard the unanimous jury right throughout the country.

Jeffrey Fisher, who argued for Ramos, plainly had a majority of justices in his corner from the start. Only Justice Samuel Alito was vocally dismissive of his argument, complaining about stare decisis (or respect for precedent). “Last term, the majority was lectured pretty sternly in a couple of dissents about the importance of stare decisis and about the impropriety of overruling established rules,” Alito said, citing the liberal justices’ dissents as the conservative majority slashed away precedent. Why, he wondered, should the court knock down Apodaca when it has served the basis for thousands of convictions? Don’t states have an interest in relying upon it?

Fisher had a good answer: Apodaca rests on a single idiosyncratic concurrence, which rests on a theory of incorporation that the court has since discredited. This argument is so strong that Louisiana Solicitor General Elizabeth Murrill did not even contest it. Instead, she argued that nonunanimous verdicts should be allowed in both state and federal courts. Put differently, the court should overturn more than a century of precedent, dislodging the unanimity rule from the Sixth Amendment.

Both Louisiana and Oregon’s nonunanimous jury rules are rooted in flagrant bigotry.

Murrill’s claim plainly irritated Justice Neil Gorsuch, who asked her: “What do we do with those 14 cases throughout Supreme Court history that seem to treat unanimity as part of the Sixth Amendment?” Murrill switched gears, asserting that the state had “enormous reliance interests” on the preservation of nonunanimous juries because “32,000 people” might challenge their convictions if Apodaca is reversed. (It is unclear why Murrill thought all 32,000 people imprisoned in Louisiana could contest their verdicts.)

“You say we should worry about the 32,000 people imprisoned,” Gorsuch responded acidly. “One might wonder whether we should worry about their interests under the Sixth Amendment as well. And then I can’t help but wonder, well, should we forever ensconce an incorrect view of the United States Constitution for perpetuity, for all states and all people, denying them a right that we believe was originally given to them—because of 32,000 criminal convictions in Louisiana?”

By then, it was clear that a majority of the court was prepared to rule against Louisiana. Justice Brett Kavanaugh even joined the pile-on: He told Murrill that “the rule in question here is rooted in racism,” in a desire “to diminish the voices of black jurors in the late 1890s.” Kavanaugh seems to have a genuine enthusiasm for eradicating racism in the jury process, and he was the only justice on Monday to bring up the racist history at hand. Why, he asked Murrill, should the court uphold Apodaca to preserve a grotesquely bigoted law designed to preserve racial injustice?

At the end of arguments, the main question was not if the court will demand unanimous verdicts, but how. Should the court overrule Apodaca, it will guarantee a retrial for defendants convicted by divided juries whose verdicts are still on appeal. That means hundreds of people in Louisiana and Oregon would get new trials. If the court declares that its decision announces a new “watershed procedural rule” of criminal law, the ruling will be fully retroactive. That would allow thousands of people convicted by split juries to demand a retrial.

No matter how broadly the court rules, any decision for Ramos would be an extraordinary shift in criminal justice. Allowing split verdicts tips the scales toward conviction, freeing a jury from the duty to find consensus. It deprives defendants of the right to have a true cross-section of the community participate equally in deliberations. More than 40 percent of felony jury verdicts in both Oregon and Louisiana are nonunanimous, driving mass incarceration in each state. A Pulitzer Prize–winning investigation by the Advocate found that black jurors in Louisiana are 2.7 times as likely as white jurors to cast a vote against the majority.

There is little chance the Supreme Court will bring justice to each and every defendant convicted by a nonunanimous jury. No solution will fully resolve the unfairness that Apodaca enabled in Louisiana and Oregon for so many decades. But the court can invalidate nonunanimous verdicts for every defendant still awaiting trial or pursuing appeal. And that will at least stamp out a Jim Crow hangover intended to ensure that, in the jury room, white voices matter more.