In order to understand the steep rise in world food prices that set off food riots in Haiti last week and toppled the government, you need to travel to Iowa. Right now, we're trying to run our cars on corn ethanol instead of gasoline. As a result, we suddenly find ourselves taking food out of the mouths of children in developing nations. That may sound harsh, but it also happens to be true.Environmentalists and farm state senators--the great biofuels coalition--of course object. After U.N. officials called for a biofuels moratorium last week, Senator Charles E. Grassley, Iowa Republican, called...