Trump’s “America first” ideology and, in particular, his controversial executive orders on immigration have sparked a public debate over what it means to be an American. A survey released Wednesday reveals deep divisions over the question, especially when it comes to religion.

Researchers at the Pew Research Center asked 1,003 U.S. adults what characteristics make someone “truly American.” By far the most important factor was the ability to speak English, which 70 percent of respondents said was a core part of the American identity. Respondents also felt strongly about sharing national traditions and customs, with 45 percent saying they were an essential part of American culture.

But those headline figures mask significant disagreements among different demographic and political groups: Republicans, for example, were much more likely than Democrats to see speaking English and “sharing American customs and traditions” as important. African Americans were more likely than white or Hispanic Americans to say being a native-born citizen is important.

The survey was conducted last spring, after Trump first called for a temporary ban on Muslim immigration but before last week’s executive order temporarily blocking travel to the U.S. from seven majority-Muslim countries. Still, the survey reveals substantial generational and demographic gaps over the role Christianity plays in American identity. Older Americans, for example, were much more likely to see religion as important: Respondents ages 50 or older were far more likely to view being a Christian as important to being American than citizens under 25 (44 percent for older Americans vs 18 percent for younger ones). More women also felt Christianity was more important to American identity than men.

There was also a partisan divide: Around 43 percent of Republicans surveyed by Pew felt that Christianity was an important part of being an American, versus 29 percent of Democrats and 26 percent of independents. Exit polls show Trump won 80 percent of white born-again and evangelical Christian voters and smaller majorities among all other denominations of Christianity.

Americans consider religion a more significant part of national identity than most other countries surveyed by Pew. The survey found 32 percent of Americans felt that it was very important to be a Christian to be considered truly American. Only two other nations in the 14-nation survey, Greece and Poland, felt more strongly than the U.S. about religion as a necessary aspect of identity. (Over half of respondents in Greece felt being a Christian was very important to their identity.) Many nations, particularly Western democracies such as Germany and France, have condemned Trump’s travel ban; the report found these countries also feel religion is much less important to identity.

Despite Trump’s calls for greater restrictions on immigration, most Americans don’t see being born in the U.S. as central to the national identity. Less than a third of respondents considered being native born “very important” to being American. Older and less-educated Americans were more likely to see birthplace as important, as were those identifying as white evangelical Christians. But even among most of those groups, only a minority considered being native-born central to being an American.

As my colleague Harry Enten wrote over the weekend, it’s hard to gauge exactly how the public will react to Trump’s latest policy proposals (though preliminary polls have shown support for the moves). But the new Pew data suggest that at least among Trump’s core group of supporters, religion plays a significant role in whether his policies are viewed as consistent with American values.