Biden faces highly charged legal fight with migrants whose children were taken away under Trump

Beatriz was 3 years old when U.S. authorities separated her from her father, Jairo, shortly after they arrived from Guatemala at the U.S. border on Christmas Eve 2017. He was detained and developed pneumonia. She was sent to New York, where a woman who took her in hit her so hard with a belt that it left a scar, she told her dad.

Ana fled Guatemala a few months later with her sons Jaime, 8, and Mateo, 7, and she says U.S. officials separated them for seven weeks, adding that...