The U.S. Supreme Court said Monday that former George W. Bush officials cannot be held liable for the abuse and detention of a group of Muslim, South Asian, and Arab non-citizens swept up in the wake of the 9/11 terrorist attacks.

"This decision regrettably provides constitutional immunity for some of the most high-level officials responsible for gross abuses in the aftermath of September 11," stated Hina Shamsi, director of the ACLU's National Security Project.

The 4-2 ruling (pdf) overturns a 2015 decision by a lower court, and marks a victory for the officials in question: former Attorney General John Ashcroft, former Federal Bureau of Investigation Director Robert Mueller (who's now serving as special counsel to investigate the ties between Russia and Trump's election campaign), and former Immigration and Naturalization Service Commissioner James Ziglar. The former wardens at the detention facility Dennis Hasty and James Sherman were also named in the case.

As the Center for Constitutional Rights (CCR), which first brought the suit forward, explains, the plaintiffs sought accountability for the officials' role "in ordering racial and religious profiling and abuse in detention, in violation of the detainees' rights under the First, Fourth, and Fifth Amendments. Our clients were held in a specially-created Administrative Maximum Special Housing Unit (ADMAX SHU), in solitary confinement. They were purposefully deprived of sleep, denied contact with the outside world, beaten and verbally abused, and denied the ability to practice their religion."

Their detention was based "on their race, religion, ethnicity, and immigration status," CCR says.

Justice Anthony Kennedy wrote for the majority: "Allowing a damages suit in this context, or in a like context in other circumstances, would require courts to interfere in an intrusive way with sensitive functions of the Executive Branch."

"The risk of personal damages liability is more likely to cause an official to second-guess difficult but necessary decisions concerning national-security policy," Kennedy continued.

The decision also noted the "telling silence" of Congress and argues that there is "a balance to be struck, in situations like this one, between deterring constitutional violations and freeing high officials to make the lawful decisions necessary to protect the Nation in times of great peril." But the "proper balance is one for the Congress, not the Judiciary, to undertake."

"We are very disappointed with the Court's dismissal of our clients' claims," said CCR senior staff attorney Rachel Meeropol. "The Court's decision allows for high-level officials to violate the Constitution without fear of personal accountability—a dangerous message in this time of rampant state-sponsored discrimination against Muslim and immigrant communities."

For one of the plaintiffs, Benamar Benatta, the ruling is "is a total failure of justice."

"To this day we see high-level officials either retired or still holding office talk and praise the effectiveness of torture and mistreatment of detainees despite mounting evidence to the contrary! It is only by holding high-level officials to account when their policies are ineffective or discriminatory that a country can properly heal and look forward to the future," Benatta said.

Justice Stephen Breyer, who was joined by Justice Ruth Bader Ginsburg, issued the dissenting opinion.

"If I may paraphrase Justice [John Marshall] Harlan," wrote Breyer, "in wartime as well as in peacetime, it is important, in a civilized society, that the judicial branch of the Nation's government stand ready to afford a remedy for the most flagrant and patently unjustified, unconstitutional abuses of official power."