With campaign spending likely to exceed $6 billion, the 2012 elections will be the most expensive in history. Why do the candidates need all that money? Because electoral success requires them to buy endless hours of television time for commercials that advertise their virtues--and, more often, roundly assail their opponents. And we all know that those sordid slanders work unless they are instantly answered with equally facile and equally expensive rebuttals.There are no easy ways to repair our election system. But a large degree of fairness could be restored to our campaigns if we level the TV playing field. Here's how to do it.