WASHINGTON — The Supreme Court on Thursday backed the Trump administration’s bid to strengthen its ability to regulate the entry of asylum seekers at the U.S.-Mexico border.

Divided 6-3, the court ruled that someone who seeks to enter the United States at the southern border cannot claim asylum if they present themselves to officials while still standing on Mexican soil because they are not technically in the United States.

The case saw conservative Justice Samuel Alito, who authored the ruling, and Justice Sonia Sotomayor, who dissented, clash openly in court as the ruling was announced.

Under federal immigration law, a person can seek asylum only if he or she is “physically present” in the country or “arrives in the United States.” The policy, first introduced in a different form by President Barack Obama in 2016, sought to prevent that requirement from being triggered by allowing U.S. Customs and Border Protection officers to block people from entering a border crossing area if the facility was deemed to be at capacity.

The court agreed that the Trump administration could reimplement that policy. Officials can once again prevent some people from applying for asylum by ensuring they cannot cross the border to present themselves to immigration officers.

Alito wrote that the ruling was based on a straightforward understanding of the law’s language.

“In ordinary speech, no one would say that a person ‘arrives in’ a place ... before the person enters the place,” he wrote.

In dissent, Sotomayor objected that the decision could have harsh implications for those seeking asylum, as it would encourage them to cross the border illegally.

“More people will die. More people will attempt to cross the border illegally, and some will make it while others will not,” she wrote.

Trump, as part of his hardline immigration policy, has sought to restrict asylum claims at the border via executive order. A federal court recently ruled against the administration on that front.

The policy was ramped up during the first Trump administration, along with other efforts to reduce the number of people seeking asylum, then rolled back during the Biden administration.

An immigrants’ rights group, Al Otro Lado, sued along with 13 individual asylum seekers.

After lengthy litigation, the San Francisco-based 9th U.S. Circuit Court of Appeals, which has jurisdiction over the U.S-Mexico border in both California and Arizona, ruled against the government in October 2024 when President Joe Biden was still in office. The court ruled that any person stopped at the border, whether they are technically in the U.S. or not, could apply for asylum.

The appeals court decision “deprives the Executive Branch of a critical tool for addressing border surges and for preventing overcrowding at ports of entry along the border,” Solicitor General D. John Sauer said in court papers.

He added that although Biden rescinded the policy, the current administration “should retain the option of reviving that practice when border conditions justify doing so.”

Lawyers for the plaintiffs say that, as the policy was rescinded, the case does not currently have any practical implications. They add that under a Biden policy introduced in June 2024, processing of asylum seekers has been limited using a different provision of immigration law.