On July 26, 1935, about a thousand anti-Nazi demonstrators attacked the SS Bremen, a sleek, state-of-the-art German ocean liner that had docked in New York. The protesters succeeded in tearing the swastika flag off the ship and throwing it into the Hudson River. It was the climax to a long, hot New York summer of street fighting between pro-Nazis and anti-Nazis.Five of the rioters in the Bremen incident were arrested, but when they appeared before Judge Louis Brodsky in September of 1935 something remarkable happened: Brodsky dismissed all charges, arguing that the swastika was “a black flag of piracy” that deserved to be destroyed, the emblem of “a revolt against civilization … an atavistic throwback to pre-medieval, if not barbaric, social and political conditions.”The law behind Brodsky’s brave proclamation was questionable, and it wasn’t long before FDR’s Justice Department apologized to Germany for the judge’s decision. Hitler praised the Roosevelt administration for disavowing Brodsky’s ruling. But the Jewish Brodsky’s acquittal of the anti-Nazi vandals still became a cause celèbre for Hitler’s party. The Nuremberg Laws of September 1935, which imposed harsh restrictions on German Jews, were, so the Nazis claimed, a “reply” to Brodsky’s “insult.”James Q. Whitman dedicates his new book Hitler’s American Model “to the ghost of Louis B. Brodsky.” But Whitman disagrees with Brodsky’s claim that the Nazism of the mid-1930s was a throwback to the Middle Ages. Whitman shows that the Nuremberg Laws, instead of being a barbarous anomaly, were in part modeled on then-current American race law. The Nazi regime saw itself at the cutting edge of racial legislation, and America was their inspiration. “Nazi lawyers regarded America, not without reason, as the innovative world leader in the creation of racist law,” Whitman remarks. In the 1930s, the American South and Nazi Germany were the world’s most straightforwardly racist regimes, proud of the way they had deprived blacks and Jews, respectively, of their civil rights.Scholars have long known that the American eugenics movement inspired the Nazis; now Whitman adds the influence of America’s immigration policy and its laws about race. Today, Whitman’s idea that Nazism looked to America for inspiration is liable to throw us into a moral panic. But there’s another side to the story, and in the Trump era, especially, we can benefit from taking a hard look at it. Our president was elected in part because he capitalized on an America-first nationalism that hunts ruthlessly for external and internal enemies. In this view, rootless cosmopolitans, immigrants, and the lawless inner cities constantly threaten the real America.***Historians have downplayed the connection between Nazi race law and America because America was mainly interested in denying full citizenship rights to blacks rather than Jews. But Whitman’s adroit scholarly detective work has proved that in the mid-’30s Nazi jurists and politicians turned again and again to the way the United States had deprived African-Americans of the right to vote and to marry whites. They were fascinated by the way the United States had turned millions of people into second-class citizens.Strange as it may seem to us, the Nazis saw America as a beacon for the white race, a Nordic racial empire that had conquered a vast amount of Lebensraum. One German scholar, Wahrhold Drascher, in his book The Supremacy of the White Race (1936), saw the founding of America as a “fateful turning point” in the rise of the Aryans. Without America, Drascher wrote, “a conscious unity of the white race would never have emerged.” Rasse and Raum—race and living space—were for Nazis the keywords behind America’s triumph in the world, according to historian Detlef Junker. Hitler admired the American commitment to racial purity, praising the anti-Indian campaigns that had “gunned down the millions of Redskins to a few hundred thousand.”In the 1930s the American South and Nazi Germany were the world’s most straightforwardly racist regimes, proud of the way they had deprived blacks and Jews, respectively, of their civil rights.Hitler was not wrong to look to America for innovations in racism. “Early 20th-century America was the global leader in race law,” Whitman writes, more so even than South Africa. Spain’s New World Empire had pioneered laws tying citizenship to blood, but the United States developed racial legislation far more advanced than that of the Spaniards. For nearly a century African-American slavery was a monumental stain on Jefferson’s Declaration of Independence and its claim that “all men are created equal.” The Naturalization Act of 1790 stated that “any alien, being a free white person” could become an American—the Nazis noted with approval that this was an unusual case of racial restriction on citizenship. California barred Chinese immigration in the 1870s; the whole country followed suit in 1882.World War I gave an added impetus to the focus of racialist doctrines on immigration and immigrants. The Asiatic Barred Zone Act of 1917 banned Asian immigrants along with homosexuals, anarchists, and “idiots.” And the Quota Law of 1921 favored Northern European immigrants over Italians and Jews, who were mostly barred from immigrating. Hitler praised American immigration restrictions in Mein Kampf: The future German dictator lamented the fact that being born in a country made one a citizen, so that “a Negro who previously lived in the German protectorates and now resides in Germany can thus beget a ‘German citizen.’ ” Hitler added that “there is currently one state in which one can observe at least weak beginnings of a better conception … the American Union,” which “simply excludes the immigration of certain races.” America, Hitler concluded, because of its race-based laws, had a more truly völkisch idea of the state than Germany did.In the area of racial restrictions on marriage, America stood alone as a pioneer. The American idea that racially mixed marriage is a crime had a strong impact on the Nuremberg Laws. In the 1930s nearly 30 American states had anti-miscegenation laws on the books, in some cases barring Asians as well as African-Americans from marrying whites. The Nazis eagerly copied American laws against miscegenation. The Nuremberg Laws, following the American model, outlawed marriages between Jews and non-Jews.In one respect American race law proved too harsh for the Nazis. In America, the “one drop” rule reigned: Often, you were counted as black if you had as little as one-sixteenth Negro blood. But the Nazi hardliners’ proposal to define Germans with one Jewish grandparent as Jews did not get approved at Nuremberg. Instead, quarter- and even half-Jews were treated with relative leniency. Mischlinge, half Jews, could be counted as Aryans, unless they were religiously observant or married to a Jew.The American treatment of voting rights was also crucial to the Nazi platform. Hitler aimed to turn German Jews into resident noncitizens who would lack the vote as well as other rights. In Mein Kampf he proposed a tripartite division between Staatsbürger (citizens), Staatsangehörige (nationals) and Ausländer (foreigners). The United States already had such a division when it came to certain ethnic groups, notably African-Americans, most of whom could not vote in the South. White Southerners saw blacks the way Nazis saw Jews, as, in Whitman’s words, an “ ‘alien race’ of invaders that threatened to get ‘the upper hand.’ ” The Nazi jurist Heinrich Krieger in a 1934 article was particularly excited that the U.S. deprived not just blacks but also Chinese of voting rights. Detlef Sahm, another legal scholar, applauded the denial of the vote to American Indians, and noted that under U.S. law Filipinos, like the Chinese, were noncitizen nationals.The Nazis were not just enthusiastic about the content of American race law, they also embraced its common-law basis. Erich Kaufmann, a right-wing German Jewish professor of law who survived the war years in hiding, praised in 1908 the way that American legal decisions, with their “wealth of life and immediacy,” as opposed to the rigid civil-law code that guided German jurisprudence, responded to “the living legal intuitions of the American people.” Thirty years later Kaufmann’s hint would be picked up by Nazis who saw common law, which embodies the powerful intuitions of the people, as a way to legislate racial prejudices. True, they conceded, there was no firm biological definition of Jewishness, but the people’s anti-Semitic instincts were nevertheless correct. Roland Freisler, one of the most radical and pitiless of Nazi jurists, wrote:I believe that every judge would reckon the Jews among the coloreds, even though they look outwardly white. … Therefore I am of the opinion that we can proceed with the same primitivity that is used by these American states. A state even simply says: ‘colored people.’ Such a procedure would be crude, but it would suffice.Freisler liked American common-law racism, with (in Whitman’s words) “its easygoing, open-ended, know-it-when-I-see-it way with the law.” Scientific definitions of race were not needed; popular bias was more than enough to go on. The American experience spoke volumes: Jim Crow racism was legal realism, rooted in the feelings of the people.Other Nazi jurists, like Bernhard Lösener, made the case against a common-law approach. They complained that individual judges could not be allowed to make judgments based on racial hunches when they had no scientific way of determining what was Jewish. “Vague sentiments of Jew hatred” were not sufficient, Lösener insisted, making the case that anti-Semitism needed a sound basis in racial “science.” Lösener stood for one side of Nazi ideology, the emphasis on the hard, scientific facts of race and peoplehood; the other side was the improvising of new rules to further German power. Improvisation won out: lack of clarity about who counted as Jewish allowed the Nazis during the war both to employ Mischlinge and to murder them if necessary.The Nazis were aware that America was run on egalitarian, liberal principles. But, they pointed out, we made race-based exceptions to our ideal. America showed, in the words of law professor Herbert Kier, that “the elemental force of the necessity of segregating humans according to their racial descent makes itself felt even where a political ideology stands in the way.” Hitler celebrated America in Mein Kampf for its gospel of social mobility, on the grounds that Nazism was an equal opportunity project for Aryans. Until the very late ’30s, FDR’s New Deal was popular among Nazis: The president, they said, had assumed dictatorial powers in order to further the prospects of all white Americans, while leaving segregation in place in the South.In his concluding pages, Whitman suggests that the Nazis’ approval of American legal culture is worth pondering. The American taste for common law, usually seen as a sign of our pragmatic, flexible approach to legal decision-making, can also enshrine popular prejudices. Popular moods like the urge to get tough on crime, or on illegal immigrants, can carry the seeds of authoritarian fanaticism.