Ignorance feeds on ignorance. Look at their constituencies: the greed (and I will not include all the rich), the under-educated, the prejudicial (includes the close-minded), followers of most types who look for leadership rather than intellectualizing problems (there's that nasty word "intellectual" which means a person who has an ability to think), the misinformed (a huge number who are not curious to independently find the answer), single issue voters (who usually fit into other categories as well), and of course NASCAR followers (pardon to the few who actually do have the ability to think through the long term ramifications of their vote, and that also applies to most other categories).
Knowledge of history and work experience. I have some under-educated relatives who don't know what the word means when someone calls their positions reactionary. I ask how well they know US and world history because their positions would return us to life as it was know before FDR and under the administrations of earlier not-so-bright Republicans, most notable, Hoover.
If they agree, which few of them do, that living under conditions as they were before the middle class started its growth under FDR, that voting for Romney, and worse yet Ryan, would assure the appointment of Supreme Court justices that would assure our conversion to a Third World country in a few decades.
I am sure I have missed a few constituency categories and would like to hear which ones I have overlooked and which you would include. I also realize we have some of the under-educated on our side as well, but those on the reactionary side are so verbose about their lack of knowledge, compassion, and understanding.
I have written about five or ten more paragraphs but this must go into a cloud and never lets me finish. When I have time I will get back to this