The matter of judicial deference to administrative agencies’ interpretations of law has seen notable developments both in Wisconsin and at the federal level in recent years. James B. Speta, the Elizabeth Froehling Horner professor at Northwestern University’s Pritzker School of Law, recently participated in a panel on the topic at the State Bar of Wisconsin’s Annual Meeting and Convention and developed his remarks into this guest post appearing on the Marquette Law School Faculty Blog on October 1, 2025.

Very near the end of its term last year, on June 28, 2024, the U.S. Supreme Court handed down one of its most significant administrative law decisions ever. Loper Bright Enterprises v. Raimondo (2024) overruled one of the Court’s own precedents, which it had relied upon for 40 years in more than a hundred decisions and which had been cited in nearly 20,000 lower court decisions. Yet not only was Loper Bright not a great surprise in federal administrative law, but it was in many ways anticipated by a decision issued by the Wisconsin Supreme Court interpreting that state’s administrative law six years earlier, Tetra Tech EC, Inc. v. Wisconsin Department of Revenue (2018).