Trump is championing an agenda of religious nationalism. Along with key White House staffers like Stephen Bannon, he believes America represents a set of values, rooted in the country’s religious identity. While there’s little evidence that Trump himself is religiously devout, he has benefited from affiliations with largely white evangelical leaders such as Jerry Falwell Jr.

During his speech, Trump argued that America’s religiously grounded values are being attacked—not just through acts of violence, but through ideological erosion. “We will not allow a beachhead of intolerance to spread in our nation,” Trump said on Thursday, seeming to refer to the “radical Islamic extremism” he has emphasized in past speeches. “You look all over the world and see what’s happening.” He will defend these values, he said, because “that’s what people want: one beautiful nation under God.”

America was not always “one nation under God”—at least, not officially. The words “under God” weren’t added to the pledge of allegiance until 1954, during the presidency of Dwight Eisenhower—not coincidentally, the first president to convene the National Prayer Breakfast. Over time, this relatively new tradition has become a mandatory exercise for commanders in chief; and during the breakfast this year, Trump specifically praised Eisenhower for kicking it off.

In many ways, Trump’s vision of religious nationalism is a continuation of Republican presidents before him. In an interview in August, the Princeton University professor Kevin Kruse pointed out that Trump’s religious rhetoric more closely resembles Nixon’s than Eisenhower’s: “He used it to justify the extent of the Vietnam War and Cambodia; he used it to advance all sorts of Silent Majority proposals before Congress,” Kruse told me. “That’s what you see in Trump today: It’s much more of a defensive pushback against people who are seen as outside one nation under God.”

This echoes recent findings of the Pew Research Center on Americans’ sense of their own national identity. While only a third of Americans believe being Christian is a very important part of being American, the numbers are split neatly along party and denominational lines: 43 percent of Republicans were likely to say that’s the case, compared to 29 percent of Democrats, and 57 percent of white evangelical Protestants said the same. Trump’s message seems to be directed toward these groups: He is affirming their sense of the tie between national and religious identity, and pushing back against those who would diminish either of those identities.

And he’s doing this through fear. In his comments at the prayer breakfast, Trump gave a graphic description of Christians being murdered overseas: “They cut off the heads, they drown people in steel cages,” he said. He also spoke “peace-loving Muslims brutalized, victimized, murdered and oppressed by ISIS killers,” and the threats against the Jewish people. He was inclusive in his description of those who are under threat, for the sake of emphasizing the need for fear: “We have seen unimaginable violence carried out in the name of religion,” he said, “acts of wanton abuse of minorities, horrors on a scale that defy description.” The fundamental threat to religious freedom, he said, is terrorism.

While Trump has often spoken about the need for safety and security, his comments at the prayer-breakfast offer a look at the ideological framework beneath that call. Like his Republican predecessors, he has aligned himself with a vision of America that is strong and powerful because of its piety. Against the threat of foreigners, terrorists, and corrupting ideologies, the United States will be one, beautiful nation—and in Trump’s view, that’s only possible under God.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.