There's no shortage of zombie movies these days. Today's audiences seem to relate to zombies in the same way that Cold War audiences in the 1950s and '60s responded to alien invaders.

Back in those days, people feared nukes and commies -- which, in the popular imagination, could easily be represented by little green men with ray guns.

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Half a century later, everybody's afraid again -- trouble is, our fears are more generalized now. We're pretty much afraid of everything from economic collapse to global warming -- and half of us are terrified of gay marriage and President Obama.

This, of course, this begs the question: What is it about zombies that particularly symbolizes today's societal fears?

Zombies are contagious, which suggests something to do with the health-care crisis. They're aggressive and hard to kill, like the insurance lobby. They wear tattered clothes and smell bad, like people who become homeless from medical debt.

So that's one theory.

Still, when you're afraid of everything, it's hard to put your finger on one fear in particular.