Since The Civil War became a phenomenon, in 1990, Ken Burns has made an art form of sprawling TV documentaries about grand American subjects: from baseball to jazz, national parks to World War II, Mark Twain to Jackie Robinson. His cinematic style—solemn narration over black-and-white photos and vintage clips, broken up by interviews with historians and quotations read by well-known actors—has become the visual language of American history. This impersonality is deliberate: in a Burns film, the filmmakers are never seen or heard on-screen, giving the impression that the story is telling itself.

The U.S. and the Holocaust, the new documentary premiering September 18 on PBS, fits a little uneasily into Burns’s ever expanding canon. There was no need to title earlier films “The U.S. and Baseball” or “The U.S. and Jazz,” because those things are obviously part of the American story. But the murder of six million Jews by Nazi Germany and its collaborators took place in Europe, mainly in Poland and Ukraine. While the Allied victory in World War II brought it to an end, it was the Red Army’s conquest of Eastern Europe that forced the Nazis to abandon Auschwitz and exposed the existence of other killing centers and mass graves.

The M.S. St. Louis was a German liner carrying more than 930 Jewish refugees from Nazi Germany.

So where do the U.S. and the Holocaust overlap, and why did Burns and his co-directors, Lynn Novick and Sarah Botstein, decide to make this documentary now? The answer lies in a third subject not named in the title but of central importance to the film: immigration policy. In telling the story of America’s decision to largely shut its doors to Jewish refugees from Nazism, the filmmakers clearly intend to rebuke those who want to close America’s borders today. Indeed, they find isolationist senator Robert Rice Reynolds of North Carolina urging the country to “build a wall” at its borders in 1941. According to Rebecca Erbelding, a historian interviewed in the film, “even though the Holocaust physically took place in Europe, it is a story that Americans have to reckon with, too.”

Historians have written a great deal about the American government’s feeble response to Nazi persecution. Between 1933, when Hitler came to power, and 1939, when he began World War II by invading Poland, hundreds of thousands of Jews hoped to flee countries that he took over or threatened. Even after the war began, almost two years passed before Germany invaded the Soviet Union, dooming millions of Jews to death by shooting and gassing. If the U.S. had opened its doors to Jewish immigrants during that time, it could have saved lives—not all or even most of those lost in the Holocaust, but hundreds of thousands.

But as The U.S. and the Holocaust shows, Americans were overwhelmingly opposed to taking in Jewish refugees. In the 1920s, Congress put an end to decades of mass immigration with a new quota system that welcomed immigration from Protestant and Nordic countries while drastically limiting new arrivals from Southern and Eastern Europe. Immigration from Asia was banned altogether.

Susi and Joseph Hilsenrath escaped from France to the U.S. in 1941.

The logic behind these laws was overtly racist. The documentary discusses the infamous Madison Grant, a conservationist turned eugenicist whose book The Passing of the Great Race helped convince the public that immigration meant race suicide. “Many white Protestant Americans came to fear … that they were being replaced,” says narrator Peter Coyote—a clear allusion to the “Great Replacement Theory” cherished today by white supremacists, including the shooter who killed 10 Black people in Buffalo, New York, in May. Now it is only such marginal figures who are openly anti-Semitic, but a century ago Jew-hatred was espoused by highly admired men such as Henry Ford and Charles Lindbergh. In a 1938 poll, two-thirds of Americans agreed that Nazi persecution was partly or entirely the Jews’ own fault.

In telling the story of America’s decision to largely shut its doors to Jewish refugees from Nazism, the filmmakers clearly intend to rebuke those who want to build a wall around America’s borders today.

The U.S. and the Holocaust acknowledges that it was not only bigotry that kept America’s doors shut in the 1930s. The Great Depression also made it tough to convince Americans to accept penniless refugees at a time when a quarter of the population was unemployed. Other nations were even more resistant. In 1938, representatives of 32 countries met in Évian, France, to discuss the problem of Jewish refugees from Germany. All expressed sympathy with their plight; only the Dominican Republic agreed to admit them. It turned out to be a propaganda coup for the Nazis, who gloated that the world didn’t want Germany’s Jews any more than Germany did.

In fact, while the U.S. could have done much more, it ended up admitting roughly 200,000 Jewish refugees between 1933 and 1945, more than any other country. Among them were Joseph and Susan Hilsenrath, who escaped from France in September 1941. When Joseph, in an interview, describes the day his ship entered New York Harbor and he saw the Statue of Liberty, the now elderly man breaks down in tears. It’s a heartbreaking reminder that for many immigrants, then as now, coming to America was the difference between life and death.

The U.S. admitted roughly 200,000 Jewish refugees between 1933 and 1945, more than any other country.

The U.S. and the Holocaust also introduces us to several would-be immigrants who could not gain entry and ended up murdered by the Nazis—such as Shmiel Jaeger, a great-uncle of the writer Daniel Mendelsohn, who helps to tell his story. Even after Nazi violence made front pages across the U.S. with Kristallnacht, the massive German pogrom in November 1938, politicians rejected emergency measures to admit Jewish refugees. “This country belongs to the people of this country,” Idaho senator William Borah declared.

That makes Borah one of the villains of the film, along with Breckinridge Long, the State Department official who resisted efforts to grant emergency visas to refugees. That is as it should be; like Pharaoh in the Bible, they hardened their hearts. But if the real subject of the film is the obligation of the U.S. to refugees, it would have been usefully challenging to Burns and company to broaden their scope beyond the Holocaust.

After all, millions of people have been killed by genocidal violence since 1945—in Cambodia, Yugoslavia, Rwanda, and beyond. Millions more have been killed in wars. Every one of them deserved to live, just like the Jewish refugees whose stories are told in The U.S. and the Holocaust. Did America have a moral obligation to make them all citizens? Perhaps—but that is an obligation of a kind that no government in history has ever recognized. One lesson of the Holocaust is that a people whose fate depends on the altruism of strangers is doomed—a lesson not lost on the men and women who, just three years after the liberation of Auschwitz, founded the Jewish state.

To hear Ken Burns reveal more about his story, listen to him on AIR MAIL’s Morning Meeting podcast

Adam Kirsch is the author of The Blessing and the Curse: The Jewish People and Their Books in the Twentieth Century and an editor for The Wall Street Journal’s weekend Review section