Ethanol is a product that would not exist if Congress didn't create an artificial market for it. No one would be willing to buy it... Yet thanks to agricultural subsidies and ethanol producer subsidies, it is now a very big business - tens of billions of dollars that have enriched a handful of corporate interests - primarily one big corporation, ADM. Ethanol does nothing to reduce fuel consumption, nothing to increase our energy independence, nothing to improve air quality."

-John McCain, November 2003

I support ethanol and I think it is a vital, a vital alternative energy source not only because of our dependency on foreign oil but its greenhouse gas reduction effects.

-John McCain, August 2006, Grinnell, Iowa

The widespread use of ethanol from corn could result in nearly twice the greenhouse gas emissions as the gasoline it would replace because of expected land-use changes, researchers concluded Thursday. The study challenges the rush to biofuels as a response to global warming.

-Associated Press, February 7, 2008 

McCain has more often than not spoken against subsidies for corn-based ethanol, and he therefore claims he's been consistent on this issue. Sort of. Here's him trying to explain his ethanol flip-floppery to Tim Russert back in 2006, when he was still planning to contest Iowa. Judge for yourself whether you find it convincing.

As for Barack Obama, winning Iowa was the linchpin of his electoral strategy, and pander he did. And Hillary Clinton? She says she opposed ethanol subsidies on behalf of her New York constituents, but supports them as a presidential candidate—big time.

Nobody, in other words, looks good on this issue right now.