Ruling also overturns judgment that allowed WWII Japanese internment camps.

WASHINGTON — In the annals of Supreme Court history, a 1944 decision upholding the forcible internment of Japanese-Americans during World War II has long stood out as a stain that is almost universally recognized as a shameful mistake. Yet that notorious precedent, Korematsu v. United States, remained law because no case gave justices a good opportunity to overrule it.

But Tuesday, when the Supreme Court’s conservative majority upheld President Donald Trump’s ban on travel into the United States by citizens of several predominantly Muslim countries, Chief Justice John Roberts also seized the moment to finally overrule Korematsu.

“The forcible relocation of U.S. citizens to concentration camps, solely and explicitly on the basis of race, is objectively unlawful and outside the scope of presidential authority,” he wrote. Citing language used by then-Justice Robert Jackson in a dissent to the 1944 ruling, Roberts added: “Korematsu was gravely wrong the day it was decided, has been overruled in the court of history, and — to be clear — ‘has no place in law under the Constitution.’ ”

In a dissent of the travel ban ruling, Justice Sonia Sotomayor offered tepid applause. While the “formal repudiation of a shameful precedent is laudable and long overdue,” she said, it failed to make the court’s decision to uphold the travel ban acceptable or right. She accused the Justice Department and the court’s majority of adopting troubling parallels between the two cases.

In both cases, she wrote, the court deferred to the government’s invocation of “an ill-defined national security threat to justify an exclusionary policy of sweeping proportion,” relying on stereotypes about a particular group amid “strong evidence that impermissible hostility and animus motivated the government’s policy.”

The fallacies in Korematsu were echoed in the travel ban ruling, warned Hiroshi Motomura, a University of California, Los Angeles, law professor who has written extensively about immigration. “Overruling Korematsu the way the court did in this case reduces the overruling to symbolism that is so bare that it is deeply troubling, given the parts of the reasoning behind Korematsu that live on in today’s decision: a willingness to paint with a broad brush by nationality, race or religion by claiming national security grounds,” he said.

He added: “if the majority really wanted to bury Korematsu, they would have struck down the travel ban.”

The Korematsu ruling, an exceedingly rare modern example in which the court explicitly upheld government discrimination against an entire category of people based upon a trait like race or ethnicity, traced back to the early days after Japan attacked Pearl Harbor and the United States entered World War II.

In 1988, Congress passed a law, signed by President Ronald Reagan, providing $20,000 in reparations to each surviving detainee. A dozen years later, Supreme Court Justice Antonin Scalia invoked Korematsu as one of the most notorious mistakes of the court, alongside the Dred Scott decision, the pre-Civil War case denying freedom and citizenship to black slaves brought into free states.

A district court judge vacated Korematsu’s conviction in 1984, citing in part the discovery that the Roosevelt era Justice Department had misled the judiciary about the need for the policy, including by citing claims that Japanese-Americans were signaling offshore submarines that the executive branch had already decided were probably not true.