Ethanol: economic gain or drain?

source: The Regional Economist
"In 2005 and 2007, two pieces of energy-related legislation with potentially far-reaching consequences became law. A key feature of these bills was a federal mandate to substantially increase the production of ethanol over the next two decades. These bills were aimed at reducing U.S. dependence on foreign-produced petroleum and at addressing global climate change. Even before the federal mandate, ethanol production had been increasing rapidly since 2000. Some of this can be traced to the sharp rise in crude oil prices, which is a derivative of the rapid growth in developing nations like China. At the same time, food prices have begun to rise sharply, which is sometimes attributed to higher prices for corn, the primary ingredient in ethanol. What are the costs and benefits of the ethanol boom, and is increased production of ethanol the primary cause of rising food prices?"