Randolph Bourne’s insights are more essential to American hopes now than when he articulated them a century ago.

The most sweeping rebuke to the Trump Administration’s ethnonationalist world view can be found in the July issue of The Atlantic. That it’s the July, 1916, issue is a testament to how retrograde that world view is, and also to the prophetic insight of the essay’s author, Randolph Bourne, a young critic whose insights are more essential to American hopes now than when he articulated them a century ago.

Bourne, who was born in New Jersey, in 1886, built his reputation in the nineteen-tens writing essays that exhorted men and women of his generation to cast off stale traditions. The recently launched New Republic published his book reviews and his reports on the progressive education system of his mentor, John Dewey. But in his piece for The Atlantic, which he wrote when he was twenty-nine, the writer stretched beyond anything he had yet attempted: to meet the challenge of a national crisis. In his time, as in ours, America was undergoing rapid demographic change. Immigration levels in the first decades of the twentieth century neared all-time highs, thanks to the millions who arrived from Italy, Poland, and other countries in Southern and Eastern Europe. A hit play of 1908 supplied a metaphor for what was supposed to happen next: “America is God’s Crucible, the great Melting-Pot where all the races of Europe are melting and re-forming!”

In real life, though, this melting didn’t happen as predicted. Immigrant groups kept their languages, styles of dress, preference for certain dumplings. Many Americans feared that newly arrived aliens would import hostilities from their homelands. The year Bourne wrote his essay was the third year of the Great War. Were unmelted Germans going to fight unmelted Russians on the streets of Chicago? If President Woodrow Wilson decided to join the conflict, where would these aliens’ loyalties lie? Many American leaders called for the melting pot to get hotter, to burn away the “hyphens” that made Hungarian-Americans or Greek-Americans a group apart. The former President Theodore Roosevelt painted a dark vision of the dangers facing the country if its inhabitants failed to achieve “100 percent Americanism,” which he defined as speaking only English and feeling total and exclusive loyalty to the interests of the United States. “The one absolutely certain way of bringing this nation to ruin, of preventing all possibility of it continuing to be a nation at all, would be to permit it to become a tangle of squabbling nationalities.” A hyphenated American, he said, was no American at all.

Bourne’s essay, titled “Trans-National America,” is a bracing seven-thousand-word challenge to the morality, logic, and wisdom of that view, in his time and ours. The record of ethnic groups trying to live together in this country hadn’t been perfect, Bourne acknowledged, but considering the abysmal results of such attempts everywhere else it had been tried, he thought they coexisted here with “almost dramatic harmlessness.” What the ethnonationalists view with dread and suspicion, Bourne saw as grounds for pride and joy. “For the first time in history has been achieved that miracle of hope, the peaceful living side by side, with character substantially preserved, of the most heterogeneous peoples under the sun,” he wrote.

The fundamental error of those who insisted on a narrow definition of Americanism, as Bourne saw it, was believing that Americanism had any fixed definition at all. He made an impish reversal of our history, arguing that American identity consisted not of timeless truths handed down from all-knowing founders but from the accumulated prejudices of the ethnic group that managed to get here first. “English snobberies, English religion, English literary styles, English literary reverences and canons, English ethics, English superiorities, have been the cultural food that we have drunk in from our mothers’ breasts,” he wrote.

Bourne spoke of English snobberies from personal experience. He grew up in the stifling, Waspy town of Bloomfield, New Jersey, raised by a single mother who was somewhat awed by his precocious intelligence. (A botched use of forceps had left Bourne’s face deformed at birth, and a childhood illness had caused his back to hunch. He speculated that these disabilities might explain his radical outlook, the sympathy he instinctively felt for outcasts and failures. If so, he wrote, “the price has not been a heavy one to pay.”) Only his arrival at Columbia University let him escape his narrow upbringing and begin “to breathe a larger air.” In his Atlantic essay, when he suggested that friendships with people from diverse backgrounds—Austrian, Scandinavian, Italian, Jewish—could give young men and women a cosmopolitan view, he was describing his own experience. By coming together in a spirit of “intellectual sympathy,” by talking and arguing and dreaming, he and his college friends made their differences “creative.”

Those late-night conversations suggested to Bourne a new way of thinking about the immigrant’s place in America. Freedom for people newly arrived in this country isn’t the absence of coercion; it’s not the result of benign neglect. Freedom means active participation in self-government, “a democratic cooperation in determining the ideals and purposes and industrial and social institutions of a country.” Bourne’s travels for a book on progressive education, and his phenomenally wide reading, showed him that this participation was good for established communities as well as for new immigrants. He compared the brisk, progressive cities of the Upper Midwest, where German and Scandinavian immigrants played leadership roles, with the South, which clung more tightly than any other region to Anglo-American ways—and, in Bourne’s view, had paid a price.

To Bourne, America wasn’t some citadel in need of defending: it was a project, one that continually enfolded new participants, dynamically renewed its character. The ethnonationalist looks backward for familiarity, security, a sense of control. Bourne, the child of a hopeful century, looked ahead with ecstatic optimism: “America is a unique sociological fabric, and it bespeaks poverty of imagination not to be thrilled at the incalculable potentialities of so novel a union of men.” Other cosmopolitans, such as the philosopher Horace Kallen, had articulated the shortcomings of the melting pot, but Bourne was rare in his ability to glimpse the shining ideal that could replace it: the “Beloved Community,” a new kind of society in which citizens are bound together by the loyalty of each to all, regardless of race or creed. Bourne was the first American to extract that concept from the work of the philosopher Josiah Royce and hold it up as the ultimate fulfillment of our national project; the second to do so, forty years later, would be Martin Luther King, Jr.

Donald Trump’s call to “Make America Great Again” would outrage Bourne: How is it, he would want to know, that, in the second decade of the twenty-first century, we are still indulging in the kind of “tight and jealous nationalism” that had sent the European powers into a suicidal war and wreaked so much havoc on America itself? How have we learned nothing from the disasters of Bourne’s own generation? Less than a year after he wrote his essay, the United States joined the war on the Allied side, unleashing a wave of “100 percent Americanism” more virulent than he had dreamed possible. Nativist attacks, vigilantism, race riots, and censorship were inflicted on a terrorized citizenry, native-born and immigrant alike. People who spoke German were menaced by mobs, and sometimes killed in the streets; the Socialist press was all but shut down, leading to a full-fledged Red Scare. As Bourne took bolder and bolder stands against the war—even denouncing his mentor, John Dewey, who thought the war would promote democratic ideals—he found it more difficult to get published. Old friends fell away; prewar hopes went to pieces. He died in the influenza pandemic of 1918, at the age of thirty-two.

Bourne wouldn’t be surprised that Americans still feel the tug of nationalist sentiment. He knew that people need to feel that they belong to a group. The unique challenge of America, a teeming “nation of nations,” is to define itself in terms broad enough to suit its transnational population, not to mimic other countries’ exclusive, backward-looking pride. “We must perpetrate the paradox that our American cultural tradition lies in the future,” he wrote. In other words, it’s false to our history, and disastrous for our prospects, to think that we can return to a mythic greater past. Those us who are here now have the chance to make something better than our forebears made, and the obligation to try.