History is repeating itself. This time without even the pretext of war, and with added heartbreaking cruelty. Under Mr. Trump’s “zero tolerance” border enforcement policy, nearly 3,000 children were separated from their parents, and while the administration later halted these separations, it neglected to keep proper records and is now struggling to find and reunite families.

Once again, national safety is invoked to justify the roundup of whole groups of people. Once again, racist stereotypes are being used by politicians to ramp up fear and hatred. And once again, lies are being used to justify actions that violate the most fundamental American ideals of freedom, equality and tolerance.

My mother and her sister were young women — not frightened and helpless children being separated from their parents, as on the border today — and they and my grandparents were allowed to remain together as a family. Even so, their “evacuation” from the house where they’d lived for 15 years split their lives into a before and after.

Before, they lived what my mother called a “regular life” in Berkeley, Calif. — in a three-bedroom stucco bungalow with a front porch, where my grandfather used to hang an American flag on holidays. My grandmother cooked rice instead of potatoes, wrote poems in Japanese and tried, without much success, to teach her daughters the language. The girls learned that being Japanese made them less than welcome by some neighbors. My aunt recalled cautiously asking questions like: “Can we come swim in the pool? We’re Japanese.”

But they longed to fit in. They were American citizens, and they thought of themselves as just as American as their classmates. They took piano lessons, went to Sunday school every Sunday and grew up reading National Geographic and Life magazine, which would later do a feature on one of the concentration camps designed to house “potential enemies of the United States.”