In Tetra Tech EC v. DOR, the Wisconsin Supreme Court became the first court in the country to eliminate deference to agency interpretations of law on the grounds of procedural due process. The lead opinion found deference violated two constitutional principles: separation of powers and procedural due process. The case primarily emphasized the separation of powers violation. But both proponents and critics of agency deference reference separation of powers to support their position. Many deference doctrines, including federal Chevron deference, find primary support in separation of powers and the understanding that agencies wield legislative authority. Further adding to the confusion, courts do not always take a clear approach to separation of powers. Procedural due process, alternatively, deals with competing litigants in the courtroom. The judiciary owes litigants an impartial tribunal. But when a judge submits to one party's interpretation of the law solely because of who that party is, the judge ceases to act impartially and violates both parties' due process rights.
The judiciary functions both as a branch of government with a duty to respect the other branches and as an impartial tribunal with a duty to individual litigants. When the two roles colliqe, which prevails? This Note argues procedural due process must prevail. It focuses on the implications of the procedural due process argument and contrasts it with the separation of powers and other arguments for agency deference. It concludes that if deference violates procedural due process, it presents a serious constitutional problem every time a court defers to an agency's interpretation of law regardless of the justification.
