Why People Vote Republican

This is a very, very interesting perspective on the titular question and helps us understand why the GOP Faithful remain so despite evidence that they should not (if you dare click over, it's a long but worthy post):

...We psychologists have been examining the origins of ideology ever since Hitler sent us Germany's best psychologists, and we long ago reported that strict parenting and a variety of personal insecurities work together to turn people against liberalism, diversity, and progress. But now that we can map the brains, genes, and unconscious attitudes of conservatives, we have refined our diagnosis: conservatism is a partially heritable personality trait that predisposes some people to be cognitively inflexible, fond of hierarchy, and inordinately afraid of uncertainty, change, and death. People vote Republican because Republicans offer "moral clarity"—a simple vision of good and evil that activates deep seated fears in much of the electorate. Democrats, in contrast, appeal to reason with their long-winded explorations of policy options for a complex world...

...But with pleasure comes seduction, and with righteous pleasure comes seduction wearing a halo. Our diagnosis explains away Republican successes while convincing us and our fellow liberals that we hold the moral high ground. Our diagnosis tells us that we have nothing to learn from other ideologies, and it blinds us to what I think is one of the main reasons that so many Americans voted Republican over the last 30 years: they honestly prefer the Republican vision of a moral order to the one offered by Democrats...

...Unity is not the great need of the hour, it is the eternal struggle of our immigrant nation. The three Durkheimian foundations of ingroup, authority, and purity are powerful tools in that struggle. Until Democrats understand this point, they will be vulnerable to the seductive but false belief that Americans vote for Republicans primarily because they have been duped into doing so.