How does religion influence political attitudes? For a simple question, researchers have yet to settle on a definitive answer. But two new contributions by Matthew R. Miles and Jeremiah J. Castle offer fresh ways of thinking about the impact of religious identity and commitment.

In Religious Identity in US Politics, Miles seeks to offer “conceptual clarity” about what it means when someone chooses to identify with a religious group (p. 3). Traditionally, scholars examine the impact of religion on politics through measures of belief (the certainty that someone has of God’s existence), belonging (whether someone chooses to affiliate with a denomination), and behavior (how frequently someone attends church). But Miles argues that we should instead see religion as a social identity that can shape people’s actions even when they no longer believe, belong, or behave. Thinking about religion in this way requires understanding how religious identity can compete with other identities like partisanship and how, in certain contexts, someone’s religious identity can be a more—or less—powerful explanation for their politics.

From this starting point, Miles advances three propos