Photographer: Tomas Ayuso/Bloomberg

The U.S. Supreme Court dealt a blow to President Donald Trump on a signature issue, refusing to let him start automatically rejecting asylum bids by people who cross the Mexican border illegally.

The justices’ order, on a 5-4 vote with Chief Justice John Roberts in the majority, left in effect a lower court decision that temporarily bars the president from changing the rules for people who claim asylum after entering the country from Mexico. Justices Clarence Thomas, Samuel Alito, Neil Gorsuch and Brett Kavanaugh dissented.

Although the legal fight isn’t over, the high court rebuff of Trump’s request to block the order suggests skepticism about the administration’s legal case.

The disputed Trump policy, designed to apply for 90 days, would effectively require all asylum claims to be made at official ports of entry. The administration is separately planning to start requiring asylum seekers to wait in Mexico while their cases are being processed.

The Trump administration’s stay request was part of an aggressive effort to draw the Supreme Court into legal battles over some of the president’s most controversial initiatives.

Federal immigration law says people may apply for asylum "whether or not at a designated port of arrival" and "irrespective of such alien’s status."

‘Orderly Manner’

The administration said those words affect only where applications can be filed, leaving room for the president and Justice Department to categorically reject groups of applicants. The administration said the president is acting in response to a surge of people who cross the border illegally and claim asylum once caught.

"These measures are designed to channel asylum seekers to ports of entry, where their claims can be processed in an orderly manner; deter unlawful and dangerous border crossings; and reduce the backlog of meritless asylum claims," U.S. Solicitor General Noel Francisco argued in court papers.

U.S. District Judge Jon Tigar first blocked Trump on Nov. 19 and then extended his order on Dec. 19. He said Congress had spoken on the issue.

"Whatever the scope of the president’s authority, he may not rewrite the immigration laws to impose a condition that Congress has expressly forbidden," wrote Tigar, a San Francisco-based judge appointed by President Barack Obama, in the earlier ruling.

That ruling prompted Trump to disparage Tigar as an "Obama judge." But the decision was later upheld by a federal appeals court in an opinion written by Republican-appointed Judge Jay Bybee.

The American Civil Liberties Union, which represents organizations challenging the Trump rule, said the administration is overstating the problem. Government statistics show the number of undocumented immigrants arrested near the Mexican border is less than half what it was a decade ago, the groups said.

"For almost 40 years, Congress has not disturbed the fundamental rule that an individual fleeing persecution can apply for asylum between ports, even when the number of apprehensions between ports was significantly higher," the groups argued.

The case is Trump v. East Bay Sanctuary Covenant, 18A615.