As markets balk, the US government recommits itself to the care and feeding of renewable fuels. Lavish subsidies and volumetric mandates haven’t been enough. The administration of Barack Obama could save itself trouble and the US money by learning that subsidies and mandates never will be enough.Setting the leading renewable fuels back onto their feet won’t be easy. Fuel ethanol and biodiesel are now flat on their backs. Producers of both politically pampered fuels are struggling if not already bankrupt. Part of the reason is that recession has made business tough for everyone. But that’s far from the only problem.Dependent energyEnergy sources dependent on governmental ...