"When religion and politics travel in the same cart, the riders believe nothing can stand in their way. Their movement becomes headlong - faster and faster and faster. They put aside all thoughts of obstacles and forget that a precipice dos not show itself to the man in a blind rush until it's too late." - Bene Gesserit saying, Dune.

I think, with the utmost respect to Mr. Herbert, I would change the word "politics" here to "power". Politics is just the discussion of how to best govern a people, or to gain power, and religion probably should be in that discussion. It's a huge part of what makes up a culture. I think it's not until power and religion are vested in the same person or group of people that it becomes dangerous for all involved.