Doyce cites an an Amazon.com snippet during his review of Dawn of the Dead:
The Zombie Archetype easily accommodates almost any satire, but tends to focus on mockery of crass consumerism, blind patriotism, anti-war (or anti-militarism) sentiment, fear of pandemic disease, and science-run-amok… all of which saw a lot of satirization in the last four years, as well as in the eighties. All horror–even the worst horror–is a response to the specific pressures and issues of its era (see also: all fiction).
The two main eras of zombie-centric books and film coincide with consecutive terms of Republican presidents.
Democrats, conversely, tend to inspire vampire films.
Not sure if it’s true (the particular political timing), but it sure sounds good.