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.”

When the family first heard about the bombing of Pearl Harbor in 1941 on the radio, they dismissed it as the work of a few fanatics. But that evening, several F.B.I. men came to their house and took my grandfather away. He and dozens of other Japanese-American businessmen and community leaders in the Bay Area had been deemed “enemy aliens,” and he was sent to an Army internment camp in Montana.

In the following weeks and months, the fearmongering grew, and officials increasingly took to using racist epithets. “A Jap is a Jap,” said Lt. Gen. John DeWitt, the commander of the Western Command and the Fourth Army, in February 1942. “The Japanese race is an enemy race.” Assistant Secretary of War John J. McCloy shrugged off questions about the legality of the situation, writing “the Constitution is just a scrap of paper to me.”

After President Franklin Roosevelt signed Executive Order 9066 in February 1942, which authorized the forced removal of residents of Japanese descent from the Pacific Coast, an 8 p.m. curfew was imposed on Japanese residents there and they were ordered to turn over all “contraband,” including firearms, cameras, radios and binoculars. My mother handed over her Brownie camera to the local police. In April, the family was designated Family No. 13453 and given 10 days to pack up and vacate the house where they had lived for a decade and a half.

They were allowed to take only what they could carry. Everything else had to be sold, thrown out, given to friends or put in storage — including the piano and the rest of the furniture, books, records, paintings, rugs, linens, plates and glasses, silverware, family letters, photographs and old Christmas cards, and all the knickknacks and bits of yarn and fabric that my grandmother, a devout hoarder, had saved during her more than 25 years in America. The three of them (my grandfather was still in the internment camp in Montana) practiced trying to walk with the two suitcases they were each allowed to take. They had to give away their collie, Laddie, who, my mother later learned, died weeks after they left him.

The removal of people of Japanese descent from their homes and their incarceration in camps were executed with the same sort of political calculus of fear and bigotry that Mr. Trump is using to redefine American immigration policy. Laura Bush wrote that she was reminded of the World War II-era internment of Japanese-Americans by the images today of migrant children being sent to mass detention facilities as a result of the Trump administration’s “zero tolerance” policy on the southern border.

Justice Sonia Sotomayor of the Supreme Court pointed out “stark parallels” between the court’s ruling last month to uphold Mr. Trump’s ban on travel from several mainly Muslim countries and the court’s 1944 Korematsu ruling, which upheld the internment of Japanese-Americans. Both effectively sanctioned “a discriminatory policy motivated by animosity toward a disfavored group, all in the name of a superficial claim of national security,” Justice Sotomayor wrote.

Bigotry and conspiracy thinking lay behind the internment of Japanese-Americans and the 1944 Supreme Court decision on Korematsu, as Richard Reeves reminded us in his important 2015 book “Infamy.” In the wake of Pearl Harbor, there were newspaper editorials with headlines like “Crime and Poverty Go Hand in Hand With Asiatic Labor.” Representative John Rankin, Democrat of Mississippi, declared, “I say it is of vital importance that we get rid of every Japanese, whether in Hawaii or the mainland.” Never mind that thousands of Japanese-Americans served in the United States Army’s highly decorated 442nd Regimental Combat Team — including my mother’s cousin, Mitsuo Nitta, who served with that team in Italy while his family was incarcerated in a camp in Arizona.

A 1982 report by a congressional commission had concluded that Executive Order 9066 “was not justified by military necessity” and that the decisions to intern Japanese-Americans were animated by “race prejudice, war hysteria and a failure of political leadership.”

President Trump’s calls for a “Muslim ban” and his “zero tolerance” border policy are similarly based on lies and racist stereotypes. During World War II, Japanese-Americans were described as animals. Satirical “Japanese Hunting Licenses” were printed (“this animal has the characteristics of a skunk in appearance and odor”), and the governor of Idaho, Chase Clark, said, “The Japs live like rats, breed like rats and act like rats.”

Today, Mr. Trump has branded some undocumented immigrants as “animals” and described them as “murderers and thieves” who want to “infest our country.” In tweeting about so-called sanctuary cities, he used the word “breeding” to refer to immigrants. He also dishonestly laments the “death and destruction caused by people that shouldn’t be here,” when in fact, studies show that immigrants are less likely to commit violent crimes than American-born citizens.

President Trump not only lies with astonishing temerity and abandon, but those lies connect into equally false narratives that gin up the worst fears and prejudices of his base. For instance, there is no border crisis: In the last fiscal year, arrests of unauthorized immigrants had actually declined to levels not seen since the early 1970s. Similarly, there has been no eruption of the “American carnage” Mr. Trump described in his Inaugural Address. Although Mr. Trump’s 2016 campaign depicted the country as beset by alarming violence, the crime rate that year was near a historic low — less than half what it was in 1991.

The shamelessness and volume of Mr. Trump’s lies — The Washington Post calculated last month that he was averaging more than 6.5 false or misleading claims a day — are flooding the country in misinformation, and his lies are endlessly repeated and amplified by the right-wing media machine. We have reached the point where more than a third of the country either buys into Mr. Trump’s falsehoods or casually shrugs them off, putting loyalty to him or the Republican Party over facts, common sense and the Constitution.

“Here in the land of Buffalo Bill,” a narrator says, “the government is erecting model camp towns — towns in which they’ll live unmolested not as prisoners but free to work and paid by the United States government.”

“Bathtubs — yes, all the comforts of home,” the narrator continues. “The Japanese in America are finding Uncle Sam a loyal master despite the war.”

At the Topaz Relocation Camp, high on a desert plateau in southwest Utah that was plagued by dust storms and mosquitoes, my mother and aunt worked as preschool and elementary-school teachers for $19 a month. They and their parents lived in another one-room “apartment” furnished with four cots. Other furniture — chairs, a table, shelves — had to be constructed from scrap lumber.

For birthdays and special occasions, my mother and aunt would hunt through old newspapers and magazines for photographs of food and presents they would have liked to have given each other and their parents back home in the “outside world” — a cake, a pie, a tea set, a vase of lilacs, an Easter ham.

After the war, my grandparents eventually returned to Berkeley. My grandmother’s health had suffered from the high altitude and dust and spartan living conditions in Topaz. My grandfather, who had been an assistant manager in the San Francisco office of a Japanese import-export firm, had difficulty finding employment after the war. He was fired from a factory job that involved painting flowers on glassware, my aunt remembered, and ended up working at a friend’s dry-cleaning business.

My mother disliked talking about her wartime experiences. She did not suffer the sort of radical fear and dislocation that the young migrant children, separated from their parents today, are experiencing. But her internment at Tanforan and Topaz left her with a lasting sense of the precariousness of life — the apprehension that unexpected perils could befall one at any moment.

My aunt, Yoshiko Uchida, became an award-winning writer of children’s books, including several about the internment of Japanese-Americans during the war. She wanted to bear witness to what happened, she wrote, “with the hope that through knowledge of the past,” our nation “will never allow another group of people in America to be sent into a desert exile ever again.”