Ever since I was an undergraduate History student, working on my Senior Honors Thesis on the Disputations of Paris (1240), Barcelona (1263), and Tortosa (1413-1414) concerning the Talmud, I have maintained a deep seated respect for the power of ideas and religious in history (to the extent that many will remain loyal to them to their own economic or political detriment). I think that the unwillingness to acknowledge this fact distorts historical understanding and our evaluation of contemporary events.
These are two articles that put this quite well (whether you're a believer or not):
B. Lewis, 'The Return of Islam,' Commentary, January 1976
D. Brooks, 'Kicking the Secularist Habit,' Atlantic Monthly, February 2003,