The Supreme Court ruled Monday that the constitutional rule requiring unanimous jury verdicts in criminal trials also applies to the states, overturning a decades-old decision that allowed a few states to convict defendants by a supermajority vote.

In federal courts and the overwhelming majority of states, criminal convictions require a unanimous jury vote. Under a quirk 1972 decision, juries in state courts were allowed to convict defendants by a supermajority. Louisiana allowed convictions on a 10-2 or 11-1 vote until 2018. Oregon is the last state to allow jury convictions by a supermajority.

Six justices supported the bottom-line outcome. Justice Neil Gorsuch delivered a fractured majority opinion, while three justices issued their own separate opinions. Justice Samuel Alito dissented, joined by Chief Justice John Roberts and Justice Elena Kagan.

Monday's opinions featured a continuing debate over the force of precedent. That discussion looms large over the High Court, as retired justice Anthony Kennedy's departure called the continued validity of landmark decisions on social issues into question. Justice Brett Kavanaugh handed down a 20-page concurrence on the Court's relationship to prior holdings, his first major writing on the subject since his confirmation. The dissent, which accused the majority of giving past decisions "rough treatment," drew a somewhat unusual coalition. Though Alito and Kagan do not often make common cause in closely divided cases, Kagan has made adherence to precedent a master principle of her legal philosophy. All told, Monday's decision was something of a proxy for disputes over basic principles.

Monday's case arose in 2016 when Evangelisto Ramos stood trial in Louisiana for second-degree murder. The jury convicted Ramos 10-2 for the brutal stabbing death of 43-year-old Trinece Fedison. Ramos was sentenced to life in prison without the possibility of parole.

Ramos argued before the Supreme Court that his non-unanimous conviction was unconstitutional under the Sixth Amendment, which guarantees "an impartial jury" to all defendants. A majority of the justices agreed with Ramos.

In sections of the decision that attracted five votes, Gorsuch said the right to trial by jury has been understood to include a unanimous verdict requirement since the 14th century. Unanimity, Gorsuch continued, has been the prevailing practice throughout American history.

"Wherever we might look to determine what the term ‘trial by an impartial jury trial' meant at the time of the Sixth Amendment's adoption—whether it's the common law, state practices in the founding era, or opinions and treatises written soon afterward—the answer is unmistakable," the decision reads. "A jury must reach a unanimous verdict in order to convict."

Gorsuch also noted that state laws allowing conviction by a supermajority have a racist pedigree. Louisiana and Oregon first adopted laws allowing non-unanimous verdicts during the Jim Crow era, with the specific purpose of diluting the influence of black jurors.

"Courts in both Louisiana and Oregon have frankly acknowledged that race was a motivating factor in the adoption of their states' respective non-unanimity rules," Gorsuch wrote.

In dissent, Alito chided the majority's reliance on the racist origins of non-unanimity rules. He noted that Louisiana and Oregon have since readopted their jury verdict requirements without racist motive, while other jurisdictions such as Puerto Rico and the United Kingdom permit non-unanimous jury verdicts.

"Too much public discourse today is sullied by ad hominem rhetoric, that is, attempts to discredit an argument not by proving that it is unsound but by attacking the character or motives of the argument's proponents," Alito wrote. "The majority regrettably succumbs to this trend."

That non-unanimous jury verdicts have survived in state courts is something of a fluke.

In a 1972 decision, Apodaca v. Oregon, five justices agreed that jury verdicts in federal court must be unanimous. But a different coalition of justices also said the unanimity requirement does not apply in state courts. Justice Lewis Powell was responsible for that discordant result. In a solo opinion, he made a defense of "dual track incorporation" or the idea that the protections of the Bill of Rights operate differently at the state and federal level.

How to handle Apodaca deeply divided the Court on Monday. Three justices—Gorsuch and Justices Ruth Bader Ginsburg and Stephen Breyer—said Apodaca never supplied "a governing precedent," meaning it need not be treated as a controlling case. Justice Sonia Sotomayor handed down a separate opinion that treats Apodaca as controlling, but nonetheless argues it should be overturned since it strangely reflects "a universe of one." In still another separate opinion, Justice Clarence Thomas outlined his own approach to the case that sidestepped Apodaca altogether.

The dissent countered that Apodaca should remain in place because two states have conducted criminal trials for decades on the assumption that supermajority jury verdicts are constitutional. Monday's decision raises the possibility that inmates in Louisiana and Oregon will seek new trials, Alito warned.

"For 48 years, Louisiana and Oregon, trusting that Apodaca is good law, have conducted thousands and thousands of trials under rules allowing non-unanimous verdicts," Alito wrote in dissent. "Now, those states face a potential tsunami of litigation on the jury unanimity issue."

"At a minimum, all defendants whose cases are still on direct appeal will presumably be entitled to a new trial," the dissent adds.

The case is No. 18-5924 Ramos v. Louisiana.

Ramos v. Louisiana decision by Washington Free Beacon on Scribd