Well known security guru Bruce Schneier has an interesting blog posting titled The Politics of Security in a Democracy. It tells that terrorism causes fear, and we overreact to that fear. Our brains aren’t very good at probability and risk analysis: We think rare risks are more common than they are, and we fear them more than probability indicates we should. Our leaders are just as prone to this overreaction as we are. But aside from basic psychology, there are other reasons that it’s smart politics to exaggerate terrorist threats, and security threats in general. Neatly summarized. Great essay.