“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,” Justice Gorsuch wrote.

In dissent, Justice Samuel A. Alito Jr., joined by Chief Justice John G. Roberts Jr. and, for the most part, Justice Elena Kagan, said the majority’s discussion of race was part of a trend in “too much public discourse today” that “attempts to discredit an argument not by proving that it is unsound but by attacking the character or motives of the argument’s proponents.”

Justice Alito wrote that the Apodaca decision deserved respect and that overruling it would lead to “a potential tsunami of litigation.” In Oregon alone, he wrote, more than 1,000 defendants with pending appeals may be able to challenge their convictions, to say nothing of post-conviction challenges that may be available in both Louisiana and Oregon.

Justice Gorsuch said that burden, whatever its magnitude, was not a good enough reason to keep the Louisiana and Oregon laws in place. “The dissent would have us discard a Sixth Amendment right in perpetuity rather than ask two states to retry a slice of their prior criminal cases,” he wrote. “Whether that slice turns out to be large or small, it cannot outweigh the interest we all share in the preservation of our constitutionally promised liberties.”

The clashing opinions were mostly a debate over respect for precedent, a topic that has recently consumed and divided the justices as they prepare to confront a potential case on the fate of the constitutional right to abortion established in 1973 in Roe v. Wade. The upshot was a remarkably tangled set of opinions.

As summarized by Justice Brett M. Kavanaugh in a concurring opinion, it appeared that “six justices treat the result on Apodaca as a precedent” and “a different group of six justices concludes that Apodaca should be and is overruled.”

Justice Ruth Bader Ginsburg and Stephen G. Breyer joined all of Justice Gorsuch’s opinion, including a passage that said the Apodaca decision was not entitled to be treated as precedent. In addition to Justice Kavanaugh, Justices Clarence Thomas and Sonia Sotomayor each filed separate concurring opinions.