WASHINGTON - The Supreme Court has upheld President Trump's travel ban on Tuesday by a 5-4 vote, saying in its opinion that the order is "squarely within the scope of Presidential authority."

The 5-4 decision Tuesday is the court's first substantive ruling on a Trump administration policy.

Chief Justice John Roberts wrote the majority opinion, joined by his four conservative colleagues. Roberts wrote that presidents have substantial power to regulate immigration. "The sole prerequisite," Roberts wrote, is "that the entry of the covered aliens 'would be detrimental to the interests of the United States.' The President has undoubtedly fulfilled that requirement here." Roberts pointed out that Mr. Trump had ordered an evaluation of every country's compliance with the risk assessment baseline and then issued the findings.

"Based on that review, he found that restricting entry of aliens who could not be vetted with adequate information was in the national interest," Roberts wrote.

The court may have signaled its eventual approval in December, when the justices allowed the policy to take full effect even as the court fight continued and lower courts had ruled it out of bounds.

In a tweet from the ACLU, the advocacy group said "this is not the first time the Court has been wrong, or has allowed official racism and xenophobia to continue rather than standing up to it."

The Associated Press contributed to this report