Why? Gallup’s Frank Newport looked at the question and came up with a simple and not-shocking answer: Evangelical support for Trump follows from the fact that they’re mostly Republican.

Overall, evangelical voters (defined by Newport as those who are white and Protestant and attend religious services nearly every week) are less supportive of Trump than are Republicans overall.

But that’s because some evangelical voters are Democrats. Among Republican evangelicals, approval of Trump is essentially the same as nonevangelical Republicans, just as support among evangelical Democrats mirrors nonevangelical Democrats.

Among evangelicals who identify as independent, Trump sees stronger approval than among nonevangelical independents.

But this, too, is linked to partisanship. Most independent voters tend to vote heavily with one party or the other. Among Republican-leaning independent evangelicals, Trump approval mirrors nonevangelical Republicans. The same pattern holds for Democratic-leaning independent evangelicals.

That evangelical support for Trump would be so strong, then, isn’t a surprise given how heavily Republican that group is. Pew Research Center data estimate that more than three-quarters of evangelicals identify as Republican or Republican-leaning independents.

Overall, a third of the Republican Party identifies as evangelical, according to Pew. By contrast, only a third of Democrats are white Protestants — evangelical or not.

The suggestion made by Newport is that party is a stronger driver of political views than religion. That mirrors other Pew research from October 2017, in which researchers determined that party identification was by far a bigger predictor of views on political values than any other demographic divide.