A U.S. Supreme Court case originating at the U.S.-Mexico border in San Diego County could determine whether asylum seekers can be turned away before they cross onto U.S. soil.

At the center of the case is how federal law defines when someone has “arrived” in the U.S. The case could provide the Trump administration a renewed pathway to limit asylum claims by turning migrants away before they enter the country.

“Does it mean physically present, or is arrival more of a process?” legal analyst Dan Eaton said.

Eaton said based on oral arguments Tuesday, the Supreme Court’s conservative majority is likely to side with the Trump administration in the case, Noem v. Al Otro Lado.

“There are people who have a credible fear of persecution who won’t even be able to seek protection in this country,” Eaton said.

The policy at issue, known as “metering,” was first used at the San Diego southern border during the Obama administration. It was later expanded during President Donald Trump’s first term before it was rescinded in 2021, under the Biden administration.

The policy allows the government to stop asylum seekers before they cross into the U.S., where they would be entitled to make an asylum claim.

Al Otro Lado, an advocacy organization based in San Diego and Tijuana, argues migrants who reach the border have effectively “arrived” and should be allowed to seek asylum under federal law, even if they have not crossed. The refugee aid organization HIAS supports that argument and points to historical precedent.

“In the late 30s, the MS St. Louis, which was a ship that was carrying Jewish refugees coming from Germany that was parked off the coast of Miami and was eventually turned back. And nearly all of the people on that ship were killed in the Holocaust,” HIAS CEO Beth Oppenheim said. “And this case echoes so much of that.”

Lower courts have sided with migrants in the case.

San Diego Congressman Darrell Issa joined a brief urging the Supreme Court to overturn those rulings and uphold the policy, writing the lower courts’ decision “defies text and common sense, and—if not reversed—it will yield untold chaos at the southern border.”

The case also raises broader questions about presidential authority over immigration policy, as allies of the Trump administration argue lower courts have limited the president’s ability to enforce his agenda. A ruling is expected in late June or early July.

This story was originally reported for broadcast by NBC San Diego. AI tools helped convert the story to a digital article, and an NBC San Diego journalist edited the article for publication.