Mother Jones: You’ve heard the rumors that the Pentagon engineered 9/11. You know about the folks who think Barack Obama wasn’t born in America. Last summer you learned every possible synonym for “death panel.” But have you heard the one about the cow tax? Unless you’re a farmer, probably not. This one goes back to the waning days of the Bush administration, when the EPA, after a long fight from environmentalists, grudgingly released a preliminary notice that outlined how the Clean Air Act could be used …