Ethanol made from corn has provoked some of the most contentious debates over U.S. agricultural and energy policy. Since the 2005 Energy Policy Act and the 2007 Energy Independence and Security Act required refineries to blend an ever-increasing amount of ethanol—currently 15 billion gallons—into the U.S. gasoline supply, farmers, agribusiness, and Corn Belt politicians have fiercely defended corn ethanol.
Yet it has been attacked by environmentalists—who emphasize the ecological harm of intense biofuel mono-crop farming and corn ethanol’s limited reduction of greenhouse gases—and libertarians and limited-government advocates who argue ethanol mandates are little more than a subsidy to agribusiness...