The increasing cultural references to the phrase "zombie apocalypse" have finally caught my attention. As I understand it, the phrase is apparently the independent invention of bloggers, one in the entertainment industry, the other in the video game industry. The zombie character is tailor made for video games, but is related to such movie horrors as vampires (because they're described as "undead"), killers that can't be killed (like Jason), pod people and triffids (because they spread their own kind -- come to think of it, vampires are included here, too). According to David Hambling ("How to Survive a Zombie Apocalypse," the zombie idea originated in Voodoo, but the notion of a zombie-like creature can be traced to earlier European literature. See Homunculus, and note that Hollywood's concept of Frankenstein's monster is decidedly more zombie-like than Mary Shelley's original conception!)
The zombie is essentially a paranoid, nightmarish fantasy. As such, it makes a perfect video-game foe. More recently, it seems to have made an incursion into political discourse, inspiring the equivalent of zombie flash mobs turning up during a demonstration and even a zombie candidate for President. One wonders what inspired this adaptation, since the notion of a zombie apocalypse clearly predates the Tea Party Movement.
Indeed, its possible one can find a precursor of the zombie apocalypse idea in the StarTrek notion of the Borg Collective, and many of the adaptations of the idea to political criticism are clearly similar. Wikipedia traces the fictional notion of a zombie to the movie "Night of the Living Dead," which first showed up in theaters in 1968, but the notion of human beings turned into zombie-like creatures clearly goes back further, for example to "Invasion of the Body Snatchers," which came out in 1956. It's possible, therefore, that these early cultural efforts were inspired by the zombie-like chatter of ideologues of either the Communist or Fascist persuasion, and may have served as a harmless means for the average citizen to externalize their worst nightmares about where the world was headed in their day.
Ultimately, the term zombie and the expression zombie apocalypse serves the needs of social commentary. In that sense it inherits the tradition of the related Jewish term, golem. which, used in this sense, can be traced back to early Rabbinic literature. A golem is sub-human, and made out of the same stuff from which the Almighty created Adam. In modern usage, a golem/zombie represents anyone in our social or political environment who strikes us as an unthinking clod with the same power of the vote that we ourselves have. It safely externalizes the contempt that progressives have for conservatives, and vice versa. As a tiny minority of ultra-cultivated/ultra-educated people, European Jews found themselves living the quintessential zombie apocalypse nightmare in Nazi-controlled western Europe and the Communist-controlled U.S.S.R.
In the current political climate leading up to a critical 2012 election, an election that could determine the survival or destruction of the U.S. as a viable democratic republic, each side, progressive and conservative, is utterly convinced of its own rectitude and of the unmitigated brainlessness of their opponents. Indeed, each side appears to be experiencing a kind of paranoid hysteria regarding the potential outcome, and each side is completely convinced that their opponents are the pre-determined cause of the worst-case scenarios.
I confess that my own perspective is only slightly more nuanced than that.