White evangelical Christians voted overwhelmingly for Donald Trump, despite his well-documented character flaws and moral failings. It turns out that their support wasn’t just about hatred of Hillary Clinton or Trump’s promise to give them the Supreme Court of their dreams.

A new study points to another more disturbing motivating force: Christian nationalism.

The study was conducted by scholars at Clemson University, East Tennessee State, and the University of Oklahoma. “The more someone believed the United States is—and should be—a Christian nation, the more likely they were to vote for Trump,” the researchers found.

The scholars looked at whether people agreed or disagreed with half a dozen statements, such as “The federal government should declare the United States a Christian nation.” Voters who scored high on that scale believed that “Trump would defend what they saw as the country’s Christian heritage — and would help move the nation toward a distinctly Christian future,” the study’s authors wrote in a Washington Post column.

The only other cultural explanation that predicted voting behavior so powerfully was the level of fear and antagonism toward Muslims. Of course, the two are not unrelated.

Some Christian-nation advocates promote false history, claiming that the First Amendment’s protections for religious liberty were meant only for Christians. Some prominent conservative activists argue that American Muslims are not protected by the First Amendment, going so far as to claim that Islam is not even a religion, or that Muslims cannot truthfully take an oath to uphold the Constitution.

Sad to say, these attitudes aren’t restricted to a few folks out on the far fringes.

The Family Research Council, for example, hosts an annual gathering of Christian conservative activists that Trump has attended both as candidate and as president. FRC president Tony Perkins has gushed about how often he’s invited to the White House, and former FRC staffers have taken influential jobs in the administration.

Perkins defended Trump’s 2015 call for a ban on Muslims entering the U.S., saying that “only 16 percent of Islam is a religion—the rest is a combination of military, judicial, economic, and political system.”

Perkins’ colleague and FRC’s executive vice president, retired General Jerry Boykin, has a long track record of anti-Muslim rhetoric, including the claims that Islam is not a religion and that Muslims do not deserve First Amendment protections.

Rhetoric that implies that “real” Americans are Christian—like rhetoric that implies that “real” Americans are white—isn’t only wrong, it’s dangerous.

Rhetorical attacks on immigrants and Muslims by Trump and his allies, and the promotion of anti-Semitic tropes by some of his fans in the alt-right, have contributed to a spike in anti-Semitic incidents and hate crimes directed at immigrants, Muslims, and even people wrongly perceived by attackers to be immigrants or Muslims.

That harm isn’t just limited to people in the United States, either.

At a recent event sponsored by Georgetown University’s Institute for the Study of Diplomacy, former diplomats warned that the rise in religious intolerance at home—specifically anti-Muslim bigotry and ethno-nationalism—threatens the ability of the United States to advocate effectively for the human rights of religious minorities facing sometimes brutal repression in other parts of the world. One speaker noted that the rise in anti-Muslim bigotry in the U.S. acts as a recruiting tool for terrorist organizations.

Rejecting America’s commitment to religious pluralism is therefore not only a betrayal of American values, which contributes to a growing climate of intolerance in the United States. It also represents the abandonment of people around the world who look to America and American ideals for hope.

Peter Montgomery is a senior fellow at People For the American Way. Distributed by OtherWords.org.