For much of the past year, analysts have claimed that a host of political factors are inhibiting hiring—regulation, the fiscal cliff, the sequester, the debt ceiling, the reelection of a socialist. Powerful forces, indeed. But there’s another force at work—more powerful, more ubiquitous, and arguably more delicious: Doritos Locos Tacos. The neon-orange, meat-filled miracle taco, wrapped in a Nacho Cheese Dorito shell, was Taco Bell’s biggest hit of 2012, with 375 million sold, or roughly one million a day. It was largely responsible for the chain’s incredible growth, outpacing not just KFC and Pizza Hut, but even McDonald’s. “It has...