I want to urge you to go over to Common Dreams and read an article by George Lakoff entitled "Untellable Truths". It's really impossible to excerpt adequately and so I truly recommend reading the whole piece. It's not very long and will not take a lot of your time.
George Lakoff is a professor of Cognitive Science and Linguistics at the University of California at Berkeley. His specialty is how various parts of the brain are activated by the kind of language we use. Lakoff is the one who has brought the notion of "framing" to public attention. To my mind he offers the best explanations yet about how Democrats tend to shoot themselves in the foot.