New York Times: When VeraSun Energy inaugurated a new ethanol processing plant last summer in Charles City, Iowa, some of that industry’s most prominent boosters showed up. Leaders of the National Corn Growers Association and the Renewable Fuels Association, for instance, came to help cut the ribbon – and so did Senator Barack Obama. Then running far behind Senator Hillary Rodham Clinton in name recognition and in the polls, Mr. Obama was in the midst of a campaign swing through the state where he …