As Mr Black above suggests - the answer lies in the use of symbols via mass media, and clever distortions of language and concepts. That people vote against their own self-interest due to the manipulation of mass psychology was noted by Orwell & Huxley in the 1930s, and they tried to warn us. It's depressing that it still happens after it has all been so well exposed, also by Hannah Arendt's The Origins of Totalitarianism which I'm currently re-reading. Scary.