...it gets to the core answer as to why the concept of good political judgment is so profoundly controversial or like my former colleague, the late Amos Tversky, said, what is it about politics that makes people so dumb?

Why Foxes Are Better Forecasters Than Hedgehogs. video/talk by Philip Tetlock.
http://fora.tv/2007/01/26/Why_Foxes_Are_Better_Forecasters_Than_Hedgehogs