Many, many Christians believe they are subject to religious discrimination in the United States. A new report from the Public Religion Research Institute and Brookings offers evidence: Almost half of Americans say discrimination against Christians is as big of a problem as discrimination against other groups, including blacks and minorities. Three-quarters of Republicans and Trump supporters said this, and so did nearly eight out of 10 white evangelical Protestants. Of the latter group, six in 10 believe that although America once was a Christian nation, it is no longer—a huge jump from 2012.

Polling data can be split up in a million different ways. It’s possible to sort by ethnicity, age, political party, and more. The benefit of sorting by religion, though, is that it highlights people’s beliefs: the way their ideological and spiritual convictions shape their self-understanding. This survey suggests that race is not enough to explain the sense of loss some white Americans seem to feel about their country, although it’s part of the story; the same is true of age, education level, and political affiliation. People’s beliefs seem to have a distinctive bearing on how they view changes in American culture, politics, and law—and whether they feel threatened. No group is more likely to express this fear than conservative Christians.

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.

None of this quite explains why many Christians believe they face discrimination, though. Suspicion of those who are different, along with a yearning for an idyllic past, are different from the perception that American Christians are penalized for their faith.

Many Christians seem to worry about their future religious liberty in the face of changing cultural and legal standards. When Donald Trump met with more than 1,000 predominantly evangelical leaders in New York City in June, religious liberty was apparently the number one topic of interest for the audience, out of tens of thousands of question submissions. This topic has consistently come up in statehouses around the country, especially in the last year; legislators feel the need to pass protections for business owners and individuals who object to gay marriage, abortion, and other acts that raise their religious concerns.

Recent Supreme Court decisions have no doubt added to that feeling of urgency. The same-sex marriage decision last summer set off a wave of state-level religious-freedom bills, and decisions just this week on abortion and birth control have raised objections from conservative Christians.

Surveys are a blunt instrument for understanding culture—more of a weather vane than a Doppler radar.

While it’s undeniably true that the country is becoming more accepting of cultural mores that are at odds with many conservative Christians’ teachings, it’s also not exactly right to say that conservative Christians are losing. The Supreme Court’s 2014 decision in Hobby Lobby was a strong defense of private business owners’ right of conscience, and state legislatures have successfully passed protections for religious people in recent sessions. The more important point is that these questions are now in play: More and more cases, legislation, and trends in public opinion are challenging the religious teachings and practices of conservative Christians.

In all of this, the standard caveats about polling apply. No single identity factor can explain why people answer surveys the way they do. Education, for example, makes a huge difference in how people responded to the question about discrimination against Christians: Only 38 percent of college-educated whites agreed that discrimination against Christians is a problem, compared to 62 percent of their working-class peers.

Shorthand about religious groups can also be misleading. While it’s useful to look at trends and patterns among one denomination or population subset, there’s enormous diversity in how even conservative Christians approach questions of cultural change and religious disaffiliation. Surveys are a blunt instrument for understanding changes in culture—more of a weather vane than a Doppler radar.

And yet, these results are a reminder that people’s beliefs matter. Religious convictions shape people’s specific fears about cultural change and newcomers, and they have those fears partly because they care about being able to practice their faith freely. Those who disagree with these Americans might offer easy explanations, from bigotry to xenophobia to stupidity, to explain their feelings of fear, but those reasons don’t seem sufficient. America is not just changing demographically—it’s becoming more religiously and ideologically diverse. Some Christians seem to feel that change acutely, and wonder whether the new era of diversity will leave room for what was once assumed to be the standard of American belief.