SAN DIEGO — A federal judge on Friday prohibited the separation of families at the border for purposes of deterring immigration for eight years, preemptively blocking resumption of a lightning-rod, Trump-era policy that the former president hasn’t ruled out if voters return him to the White House next year.

The separation of thousands of families “represents one of the most shameful chapters in the history of our country,” U.S. District Judge Dana Sabraw said moments before approving a settlement between the Justice Department and families represented by the American Civil Liberties Union that ended a legal challenge nearly seven years after it was filed.

Sabraw, who was appointed by President George W. Bush, ordered an end to separations in June 2018, six days after then-President Donald Trump halted them on his own amid intense international backlash. The judge also ordered that the government reunite children with their parents within 30 days, setting off a mad scramble because government databases weren’t linked. Children had been dispersed to shelters across the country that didn’t know who their parents were or how to find them.

As he reminisced and congratulated lawyers on both sides, the judge recalled a sense of horror over initial allegations and how subsequent disclosures left him increasingly dismayed over how the policy was carried out in 2017 and 2018. He read from an earlier order in which he said the practice was “brutal, offensive and fails to comply with traditional notions of fair play and decency.”

Sabraw referred to another court filing in 2018 that described how many parents were deported without knowing where their children were. “Simply cruel,” he said.

The government and volunteers have yet to locate 68 children who were separated under the policy to determine if they are safe and reunited with family or loved ones, according to the ACLU. Sabraw said those children who are unaccounted for was “always my greatest fear and concern.”

Under the settlement, the type of “zero-tolerance” policy under which the Trump administration separated more than 5,000 children from parents who were arrested for illegally entering the country would be prohibited until December 2031.

Children may still be separated but under limited circumstances, as has been the case for years. They include if the child is believed to be abused, if the parent is convicted of serious crimes or if there are doubts that the adult is the parent.

Families that were separated may be eligible for other benefits — legal status for up to three years on humanitarian parole; reunification in the United States at government expense; one year of housing; three years of counseling; legal aid in immigration court. But the settlement doesn’t pay families any money. In 2021, the Biden administration considered compensating parents and children hundreds of thousands of dollars each, but talks stalled.

As he seeks to return to the White House in next year’s elections, Trump has been noncommittal whether he would try to resume family separations. He defended the results in an interview with Univision last month, claiming without evidence that it “stopped people from coming by the hundreds of thousands.”

“When you hear that you’re going to be separated from your family, you don’t come. When you think you’re going to come into the United States with your family, you come,” Trump said.

The Department of Homeland Security referred Friday to an earlier statement by Secretary Alejandro Mayorkas that the settlement reflects efforts to address a “cruel and inhumane policy, and our steadfast adherence to our nation’s most dearly held values.”

ACLU attorney Lee Gelernt told reporters that the judge’s comments Friday “said it all. This was a tragic episode in our country’s history.”

The Trump campaign did not immediately respond to the ruling Friday.