The issue of whether courts should defer to an executive agency’s interpretation of a statute is a familiar one. Going back all the way to Marbury v. Madison, we know that courts decide the meaning of a statute. Courts therefore routinely decide how to interpret ambiguous statutes. But what happens when a statute is ambiguous and an agency tasked with enforcing that statute has interpreted the statute in a particular way? Should a court defer to that interpretation?
Under Law Court precedent, the answer to this question has been, as a general rule, yes. In Guilford Transportation Industries v. Public Utilities Commission and elsewhere, the Law Court has said that a court will defer to an agency’s interpretation of a statute it enforces if (1) the statute is ambiguous, and (2) the agency’s interpretation is reasonable. In doing so, the Law Court relied upon the U.S. Supreme Court’s decision in Chevron v. NRDC,