A mandated carbon reduction will face stiff resistance in Washington. But the modest increases in cars' fuel efficiency that many officials support as a way to curb greenhouse gases and promote energy independence do not, by themselves, go far enough. Drivers need both more efficient vehicles and the alternative of ethanol to reduce their climate change impact. A mandate on carbon emissions would make sure they can put greener gas in their tank.

CORN should be used for food, not motor fuel, and yet the United States is committed to a policy that we've touted for at least a year encourages farmers to turn an increasing amount of their crop into ethanol. This may save the nation a bit of the cost of imported oil, but it increases global-warming gases and contributes to higher food prices.