On March 20, 2013, the U.S. Supreme Court decided Decker v. Northwest Environmental Defense Center. On its surface, the case concerned whether runoff from logging roads required a permit under the Clean Water Act. Not far beneath the surface, however, was whether the federal courts had to defer to the Environmental Protection Agency’s interpretation of its own regulation. In the end, in an opinion by Justice Anthony M. Kennedy, the Court upheld EPA’s interpretation, relying in part on its earlier ruling in Auer v. Robbins, 519 U.S. 452 (1997), that agency interpretations of their own regulations are deferred to unless they are plainly erroneous or inconsistent with the regulation.
Obviously, there is a lot of "Auer deference" in the many shelf-feet of Federal Reporters. Simply stated, Auer is to regulations as Chevron U.S.A. Inc. v. Natural Resources Defense Council Inc., 467 U.S. 837 (1984), is to statutes.
