This paper examines the sources of the evangelical advantage in religious strength over other Protestant religious traditions. Christian Smith's (1998) subcultural identity theory of religious strength posits that this advantage is produced by the unique way that self-identified evangelicals interact with hostile outgroups in society. Specifically, Smith claims evangelicals maintain strong symbolic boundaries between themselves and relevant outgroups, while at the same time engaging these groups. Other major Protestant religious traditions do not maintain the correct balance between distinction and engagement with relevant outgroups – hence they display lower levels of religious strength. The effects of this interaction between religious tradition and relevant societal outgroups on measures of church attendance and self-reported importance of faith are empirically investigated. The results suggest that evangelicals do not derive their strength from interacting with hostile outgroups, thus questioning the validity of the subcultural identity theory of religious strength. Alternative explanations are explored.