In this book chapter, Michael Kessler explores the relationship between religion and U.S. foreign affairs. He argues that foreign policy leaders have recently learned to better address the religious dimensions of conflicts, although this change from secularist approaches has perhaps been slower than needed. This chapter appears in the Wiley Blackwell Companion to Religion and Politics in the U.S., edited by Barbara McGraw. The edited volume provides a broad, inclusive, and rich study of religion and politics. Arranged in their historical context, chapters address themes of history, law, social and religious movements, policy, and political theory.