One aspect of American fear that’s been talked about a lot during this presidential-election cycle is fear of the other, from the Mexican immigrants who would be kept out by a wall to the Muslim refugees who would be banned from fleeing here from their homes abroad. That fear seems to fade, though, if Americans recognize a religious kinship with people they perceive as foreign.

Forty-six percent of those surveyed said immigration from Mexico and Central America has been too high in recent years. When asked the same question about immigrants from “predominantly Christian countries,” though, only 10 percent of people said immigration has been too high. The irony is that this is essentially the same question, phrased two different ways: Latin American countries are overwhelming Christian—in many places, even more so than the United States. When Americans think of those immigrants as Christians, rather than foreign nationals, they’re more likely to open their arms in welcome.

Attitudes toward Muslims are slightly more complicated. Even though some Muslims have been in the United States for longer than many of the Protestant and Catholic descendants of German, Italian, and Irish immigrants, most Americans still believe Islam is “at odds with American values and way of life.” That includes 74 percent of white evangelical Protestants, 66 percent of white mainline Protestants, 63 percent of white Catholics, and 54 percent of Hispanic Catholics.

The way the question is phrased, invoking “American values,” is a bit of a cipher. The people being surveyed might have thought of anything from “hard work” to “liberal democracy” to “white picket fences.” But especially to those who believed that America was once a Christian nation, the question may have seemed to refer to Christianity—the soft religious vibe that has often been in the background of American politics and popular culture. For many of the people who believe Islam is “un-American,” it seems likely that they see those beliefs and practices in tension with Christianity—and perhaps a threat to it, as well.

This suspicion may be compounded by the changing demographics of American Christianity. While the U.S. is still a nation of faith, with roughly 71 percent of adults identifying as some kind of Christian, religious organizations of all kinds are struggling with lower levels of attendance and declining participation in ritual practices. More and more people say they’re not part of any religion, and this is especially true of young people in their 20s and early 30s. If religious people believe their institutions are declining—which, demographically speaking, they are—they may feel more threatened by what they perceive as the growing numbers of people in the country who have a different kind of faith.

There’s evidence of this in the strong nostalgia many people seem to feel for the past—an elusive time when Americans felt more of a consensus about their values and beliefs. Strong majorities of white evangelical Protestants and white Catholics believe America has changed for the worse since the 1950s, as do a slim majority of white mainline Protestants.