Last Friday, 19 April, the EPA issued an emergency waiver for E15 to be sold through the summer driving season. The topline takeaway of that action is positive for the ethanol sector, but the practicality of implementing the new rule is more complex.   Indeed, the structure of the Clean Air Act (CAA) regulatory scheme for E15 is cumbersome and inefficient. It is reminiscent of the contraptions depicted by the early 20th century cartoons from engineer and cartoonist Rube Goldberg. Mr. Goldberg was a famous and award-winning cartoonist who caricaturized complicated, multi-step machines, designed to perform the most basic and simple tasks. The legacy of his cartoon drawings remains today in the form of Rube Goldberg Machine contests...