The U.S. Supreme Court recently heard arguments regarding whether it should reverse or modify the now famous (or infamous) 1984 case of Chevron U.S.A. v. Natural Resources Defense Council. While that case and its numerous progenies over the last 20 years have been subject to many interpretive nuances, at bottom the decision instructed the courts to defer to federal agencies if the enabling statute at issue was ambiguous and the agency's interpretation was reasonable.