To many Americans, modern marches by the Ku Klux Klan may seem like a throwback to the past or posturing by bigoted hatemongers. To Kelly Baker, they are a reminder of how deeply the Klan is rooted in American mainstream Protestant culture. Most studies of the KKK dismiss it as an organization of racists attempting to intimidate minorities and argue that the Klan used religion only as a rhetorical device. Baker contends instead that the KKK...