The Supreme Court handed President Trump a huge legal victory Tuesday, upholding his ban on U.S. entry from several countries with mostly Muslim populations as a legitimate act of executive authority over immigration and national security.

In a 5-4 vote, the court’s conservative majority said Trump had acted within his legal power to exclude “classes of aliens” from the country based on his conclusion that their entry would be harmful to the national interest.

Long-standing federal law “exudes deference to the president” to make those determinations, Chief Justice John Roberts said in the majority opinion.

He also rejected arguments that the travel ban was an unconstitutional act of discrimination against Muslims.

Although Trump’s campaign statements calling for a ban on Muslim immigration cast some “doubt on the official objective” of his order, Roberts said, the order itself “says nothing about religion,” and the exclusions apply to only 8 percent of the world’s Muslim population.

The court’s task, Roberts said, was not to judge Trump’s comments, but only to determine whether his order has “a legitimate grounding in national security concerns.”

Trump celebrated the victory in a brief tweet Tuesday morning.

“SUPREME COURT UPHOLDS TRUMP TRAVEL BAN,” he wrote. “Wow!”

Dissenting Justice Sonia Sotomayor likened the ruling to the court’s 1944 decision upholding the internment of Japanese-Americans during World War II.

The court majority is “turning a blind eye to the pain and suffering the (presidential) proclamation inflicts upon countless families, many of whom are United States citizens,” said Sotomayor, joined by Justice Ruth Bader Ginsburg.

Justices Stephen Breyer and Elena Kagan also dissented.

This was the third version of Trump’s travel ban. The first, issued hastily a few days after he took office, froze entry to the U.S. from seven countries with overwhelmingly Muslim populations and all admissions of refugees fleeing hardship and violence in their homeland.

After days of turmoil at the nation’s airports, federal courts blocked the executive order as an act of discrimination based on religion and nationality. Judges cited Trump’s promise as a presidential candidate to ban all Muslim immigration, and a post-inauguration remark by Trump confidante Rudy Giuliani that the president had asked him to find a legal way to issue a “Muslim ban.”

The second version, in March 2017 removed Iraq from the list, at the request of Pentagon officials who counted on Iraqi assistance to combat Islamic state militants. Federal courts again rejected it as discriminatory, but the Supreme Court let parts of it take effect before it expired.

The current travel ban was announced in September, and in December the high court allowed it to be fully enforced during legal challenges. It bars most U.S. entry from five predominantly Muslim nations — Iran, Libya, Somalia, Syria and Yemen — as well as North Korea and officials from Venezuela.

The administration has argued that each of Trump’s orders was based on the president’s legal authority over admission of foreigners — the same authority invoked by presidents Jimmy Carter, in excluding admissions from Iran while its government held U.S. hostages, and Ronald Reagan, in barring Cubans during an escalation of tensions with Fidel Castro.

Disputing arguments that Muslim nations were singled out, administration officials said the final version of the travel ban was based on a review of other nation’s security policies on screening residents who travel or emigrate abroad.

Trump, meanwhile, has cut U.S. refugee admissions to a maximum of 45,000 a year — half the number under President Barack Obama —and is on pace to allow only about 20,000 this year. The reductions, decried by international refugee organizations, were not challenged in the court case.

The lead plaintiff in the case was the state of Hawaii, joined by other Democratic-majority states, including California, and advocates for immigrants and refugees. They cited the 1965 law that banned discrimination based on national origin in issuing immigration visas, and also said Trump’s order would exclude 150 million people from the United States, most of them Muslims.

Trump’s advocates countered that the number was only a small fraction of the world’s Muslim population. They disputed any reference to Trump’s campaign comments, saying they were irrelevant to the case and protected by free speech, and also cited a law that allows the president to “suspend the entry” of any group of foreigners whose presence is “detrimental to the interests of the United States.”

Roberts invoked that law in Tuesday’s ruling. He said it grants Trump “broad discretion to suspend the entry of aliens” who, in his assessment, could not be “vetted with adequate information” in their home countries.

Sotomayor, in her dissent, said the Trump administration “masquerades behind a façade of national-security concerns” to conceal a policy based in religious discrimination.

The ruling saddened and angered civil rights groups and other opponents of Trump’s policy.

The court “gave license to the worst impulses of a president who has made no secret of his racial, ethnic and religious prejudice,” said Elizabeth Wydra, president of the Constitutional Accountability Center.

California Attorney General Xavier Becerra, who filed arguments supporting Hawaii’s challenge to Trump, said, “One day, this nation and court will look back and regret this ruling that legalized discrimination.”

Stephen Yale-Loehr, a Cornell University immigration law professor who joined arguments against Trump’s order, said the ruling was unsurprising. He also said it would likely lead to a further decline in travel to the U.S.

“Even if the president cannot persuade Congress to fund his actual wall along the U.S.-Mexican border, he has erected an invisible wall for many immigrants,” Yale-Loehr said.