WASHINGTON (AP) — The Supreme Court cleared the way Thursday for the Trump administration to potentially revive an immigration policy once used to turn back migrants seeking asylum at the United States-Mexico border.

The justices, in a 6-3 decision, overturned a lower court order blocking the practice that limited the number of people who could apply for asylum each day, first under the Obama administration and then expanded during President Donald Trump’s first term.

Advocates said the tactic created a humanitarian crisis as thousands of people settled in unsafe makeshift shelters along ports of entry to await their turn for days or months.