There are many reasons for American Jews to reject Donald Trump’s inhuman treatment of the undocumented families who cross America’s borders. The Torah emphasizes the value of all people. (It doesn’t begin with Jews. It begins with Adam, Eve, Cain, Abel and Noah, who hail from no nation or tribe). The Torah repeatedly stresses our responsibility to the stranger. And, in modern times, Jews have often needed the very refuge that Central American migrants seek today.

But there’s another reason to oppose Trump’s savage nativism: It verges on idolatry. Let me explain.

In their wonderful podcast on Jewish law, Responsa Radio, Rabbis Avi Killip and Ethan Tucker of Yeshivat Hadar recently took up a question from a Jewish martial arts student who asked whether she could ceremonially bow at the end of class. From the perspective of Jewish law, Killip and Tucker explained, the key issue is what one is bowing too. You can bow as a sign of respect. In the Bible, Jacob bows to his brother Esau, Moses bows to his father-in-law Jethro, the Prophet Nathan bows to King David. What you cannot do is bow, even inadvertently, to something that is worshipped. The Talmud, they note, instructs that if you accidentally drop coins in front of an idol you should not bend down to pick them up lest you appear to be worshipping it.

This distinction might explain Mordechai’s famous refusal to bow to Haman in the Book of Esther. Why was it OK for Nathan to bow to King David but not OK for Mordechai to bow to Haman? There are many opinions. But one might be that Haman, unlike David, was fashioning himself as some sort of god.

What does this have to do with Trump and immigration? The answer lies in the way Trump depicts the American nation. He’s turning it from an object of respect into an object of worship.

Nationalism has been an animating feature of the conservative movement since its birth in the 1950s. But before Trump, the American right’s reverence for the American nation was tempered by a reverence for principles that transcended it.

One principle was capitalism. With a few exceptions, like Pat Buchanan, prominent American conservatives supported free trade even though globalization made borders more porous. Trade barriers strengthened American sovereignty, but most conservatives saw them as an offense not only against prosperity but against freedom.

The second principle that tempered the nationalism of the American right was religion. Although American Christianity often went hand in hand with American nationalism, its moral universalism sometimes restrained it. George W. Bush’s missionary zeal may have contributed to his decision to invade Iraq. But it also led him to increase funding to combat AIDS in Africa. When Bush said, in a 2006 speech on immigration that, “Every human being has dignity and value no matter what their citizenship papers say,” he was speaking not as an American nationalist but as a Christian universalist.

Trump has weakened these countervailing forces. He scorns the global capitalist system that leading conservatives once admired. He sees America’s relationship with other nations in largely competitive, zero-sum terms. He rejects virtually any moral obligation to people in other lands. And he refers to migrants seeking to enter the United States not as children of God but as “animals” who “infect” the American nation.

Trump is turning America into a kind of idol. He declared his inauguration day a day of “patriotic devotion” a word historically associated with religious piety. He announced in his inaugural address that, “At the bedrock of our politics will be a total allegiance to the United States of America.” Not just allegiance, but “total allegiance.”

When presidents have used such totalizing, hyper-nationalist language in the past, it has usually augured brutality and exclusion. The last president to declare a day of “patriotic devotion” was Woodrow Wilson at the beginning of World War I. He declared it at the same time the revived Klu Klux Klan was demanding “one hundred percent Americanism.” And World War I ushered in an era of nativist hysteria in which the Justice Department raided immigrant neighborhoods looking for radicals, towns outlawed the playing of Beethoven because he was German and vigilantes lynched German Americans in the streets.

Trump’s hyper nationalism has brought its own forms of ugliness. He has demanded that NFL owners fire players who don’t salute the flag. He has said a Mexican-American judge born in Indiana should be disqualified from hearing a lawsuit against Trump University because he’s “Mexican.” And, like Wilson, he has endorsed brutal measures against immigrants who supposedly sully the integrity of the American nation.

Nationalism, as Batya Ungar-Sargon has powerfully argued, can be a force for moral progress when linked to inclusive liberal ideals. But in Trump’s hands, it has become a heresy.

When a president suggests that Americans owe a special obligation to each other, he is making Americanism an object of respect. When Trump suggests that non-Americans constitute a different species, he is making Americanism a kind of deity. He is asking Americans to abandon instincts that make us human—our empathy for a vulnerable, terrified immigrant child—to prove our “total allegiance” to our nation.

This violates something deep in Jewish tradition, which commands Jews to be loyal to the countries in which we live, not to treat them as gods. The more Trump invokes Americanism to justify inhumanity, the more American Jews should refuse to bow down.