The process of analyzing and understanding presidential election dynamics often leads us to look at the American electorate not as a whole, but by segments. Party identification is the most frequently used way to sort voters, but other variables are also meaningfully related to political behavior and help explain how and why people vote.

Of particular interest this election cycle is the religious identity of voters, a factor that appears, at least to me, more important than it has been in recent presidential elections. This is in part because Joe Biden is only the fourth major-party Catholic presidential nominee in U.S. history and in part because Donald Trump continues to make the courting of evangelical voters a major priority of his campaign. Both the Biden and Trump campaigns have appointed coordinators to reach out to faith communities.

Segmenting Americans according to their religious identity is not as straightforward as it might seem. Religious identity is like a Russian nesting doll; opening up one doll reveals more dolls within. Broad religious groups can be divided into smaller religious groups, […]