After writing critically about Donald Trump in recent weeks, a series of Jewish journalists have expressed astonishment at the level of anti-Semitic vitriol directed their way. “I have never received the amount of anti-Semitic hate I currently do each day for the crime of criticizing The Great Trump,” noted conservative commentator Ben Shapiro. Another Trump critic, Bethany Mandel, recently wrote an essay entitled, “My Trump Tweets Earned Me So Many Anti-Semitic Haters That I Bought a Gun.”

Trump’s response to his supporters’ behavior has been coy. Asked on CNN about the torrent of Nazi imagery directed at Julia Ioffe after she profiled his wife Melania, Trump replied, “I don’t have a message to the fans. A woman wrote an article that’s inaccurate.” For her part, Melania conceded that some of her fans “maybe went too far,” but said that Ioffe “provoked them.”

Trump has said that, “Antisemitism has no place our society.” But he’s also retweeted messages from openly anti-Semitic accounts. He’s promised that the “major and overriding theme of my administration” will be “America First,” a 1930s-era slogan associated with the notoriously anti-Semitic Charles Lindbergh. And he’s told a Jewish audience that Jews love to “negotiate deals.”

So how does Trump defend himself against charges that he’s flirting with Jew-hatred? Often, he invokes his daughter Ivanka, who became an Orthodox Jew herself. In a speech to the Republican Jewish Coalition last December, Trump boasted that his daughter doesn’t answer the phone on Saturday. At a debate in March, he declared that, “I have tremendous love for Israel. I happen to have a son-in-law and a daughter that are Jewish, OK? And two grandchildren that are Jewish.”

To some extent, Trump’s defense is working. “I don’t think he’s going to go out and hurt Jews — between Ivanka, and the grandchildren ... that’s not going to happen,” Trump-supporting Rabbi Bernhard Rosenberg told Huffington Post last week. Even in detailing his own experience with Trump’s anti-Semitic supporters, New York Times reporter Jonathan Weisman felt compelled to note that, “Trump has a son-in-law who is an Orthodox Jew, and a daughter who converted to her husband’s religion. Mr. Trump has bragged about his Jewish grandchildren.”

People buy Trump’s alibi because they assume that leaders who have Jewish family and friends won’t foment anti-Semitism. It’s a reassuring notion. Unfortunately, history proves it to be patently untrue.

For years, Benito Mussolini carried on an affair with a Venetian Jewish woman named Margherita Sarfatti. He nevertheless boasted about his hatred of “these disgusting Jews,” a hatred that he claimed long preceded Italy’s implementation of anti-Semitic legislation in 1938. Lueger, the notoriously anti-Semitic turn-of-the-century mayor of Vienna who inspired Adolf Hitler, had numerous Jewish friends. Asked to explain the apparent contradiction, he declared, “I decide who is a Jew.”

In his book, The Captive Mind, Czeslaw Milosz describes an anti-Semitic writer in 1930s Poland who “had many Jewish friends, and the very day he published his racist statements, he would come to these friendsand falling on his knees, would declare his love for them.” Notorious anti-Jewish polemicists of 16th Century Central Europe, Johannes Pfefferkorn and Anton Margaritha, were both Jewish converts to Christianity. Even Hitler himself expressed deep affection toward Eduard Bloch, a Jewish doctor from Vienna who had treated his mother. Calling Bloch a “noble Jew,” Hitler instructed the Gestapo to protect him even as Nazi forces sent other Austrian Jews to their deaths.

Personal behavior often contradicts public ideology. And not only when it comes to Jews. Male politicians whose policies promote women’s rights privately abuse the women around them. Presidents who loudly extol public education send their children to private schools. Conservative Christian moralists have gay affairs. Racist politicians nonetheless treat the African Americans they know with kindness and respect. People are complicated. The impulses that drive public policy may be utterly different from the impulses that drive private actions.

So it is with Trump and Jews. I’m sure he gazes lovingly at his Jewish grandchildren from across his daughter’s Shabbat table. I’m sure he’s supportive of his many Jewish friends and business associates. But he’s running for president as the tribune of Americans who are culturally alienated from the American elite, and some of them define that elite as synonymous with Jews. Trump doesn’t want to rebuke those supporters too strongly — partly because he needs their votes and partly because his narcissism inclines him to believe that anyone who admires him can’t be all bad.

For Trump, as for many other leaders throughout history, winking at bigotry is part of a political project. It’s not personal. It’s a technique for achieving power.