Creatures of government lead strange lives. Biodiesel, for example.When the Environmental Protection Agency in July confirmed a statutory mandate that 800 million gal of biodiesel be sold in the US next year, industry leaders said producers can meet that need with existing capacity. But will they?A $1/gal biodiesel tax credit enacted in 2005 expired last December, and the latest effort to extend it retroactively failed this month in the Senate. An important production incentive remains in suspense.In the first 5 months of this year, biodiesel output totaled 159 million gal, according to the Energy Information Administration. At that rate, production would fall well shy of this year's mand...