During Thursday night’s Democratic presidential debate at Loyola Marymount University in Los Angeles, Pete Buttigieg proposed offering reparations to undocumented families that were separated under President Donald Trump’s controversial zero-tolerance policy.

The South Bend, Indiana Mayor said, should he be elected president, he would financially compensate the almost 5,500 families separated as well as offer them a “fast track” to citizenship.

“They should have a fast track to citizenship because what the United States did under this president to them was wrong,” Buttigieg said during the debate. “We have a moral obligation to make right what was broken.”

The U.S. started separating families seeking refuge in the U.S. through a small-scale program in 2017. By spring of 2018, it was expanded, with parents sent to adult detention centers and children, who are not legally allowed to be in facilities for more than 20 days, transferred to the Department of Health and Human Services’s custody, Vox reports. In the past, administrations released immigrant families together.

The zero-tolerance policy was suspended in June 2018 after massive backlash.

Since then, the American Civil Liberties Union as well as other human rights groups have filed lawsuits on behalf of separated families seeking financial damages, while Democrats in Congress have introduced legislation aimed at offering these families a path to citizenship. Last month, a federal judge ruled that the U.S. government is required to offer mental health services to the thousands of families who were separated at the border due to the controversial policy.

Buttigieg, who is a Democratic frontrunner in the 2020 race, has mentioned supporting separated families in the past. Just last month at a town hall in Iowa, he told voters that the U.S. “owes something to kids in that situation” and should try to “make things right.”