There is a wonderful blog written by Errol Morris with the title "Photography as a weapon" at

http://morris.blogs.nytimes.com/2008/08/11/photography-as-a-weapon/

I think this might require a free registration to read since it is the NY Times (you have to give them your email address and choose a password is all, I think), but I think you might find it is worth the effort. Morris is an Academy-award winning documentary film-maker and in this blog he intersperses his own views with some very interesting interviews. A good read IMHO.