The Trump administration submitted a request on Thursday to terminate a long-standing policy critical to protecting child migrants in federal custody since the 1990s, a decision that will likely face opposition from advocates.

This policy, referred to as the Flores Settlement, primarily restricts the duration that unaccompanied child migrants, or those with families and detained by the U.S. Border Patrol, can be held in U.S. Customs and Border Protection custody to 72 hours. It also mandates that the children must be housed in safe and hygienic environments.

The Flores Settlement is named after Jenny Flores, a Salvadoran girl whose lawsuit in the 1980s brought attention to the widespread mistreatment of children in custody and led to increased oversight.

This is the second time the federal government under Trump has attempted to end the policy. In August 2019, the first Trump administration asked a judge to dissolve the agreement. Its motion eventually was struck down in December 2020 by the 9th U.S. Circuit Court of Appeals.

Under the Biden administration, oversight protections for child migrants were lifted for the U.S. Department of Health and Human Services after new guidelines were put in place last year.

The Department of Homeland Security is still beholden to the agreement, including Customs and Border Protection, which detains and processes children after their arrival in the U.S. with or without their parents. Children then are usually released with their families or sent to a shelter operated by HHS, though processing times often go up when the number of people entering increases in a short time period.

Even with the agreement in place, there have been instances where the federal government failed to provide adequate conditions for children, as in a case in Texas where nearly 300 children had to be moved from a Border Patrol facility following reports they were receiving inadequate food, water and sanitation.

Court-appointed monitors provide oversight of the agreement and report noncompliant facilities to Chief U.S. District Judge Dolly M. Gee of the Central District of California. CBP was set to resume its own oversight but in January a federal judge ruled it was not ready and extended the use of court-appointed monitors for another 18 months.