The six to three decision overruling Chevron v. Natural Resources Defense Council is a watershed in the constitutional history of the administrative state and another crushing defeat for the Supreme Court’s liberal wing.

Chevron, decided four decades ago, mandated that if the meaning of a statute was ambiguous, courts must defer to the “reasonable” interpretation of an administrative agency. It is one of the most cited cases in American history, and served as the bedrock for the relationship between courts and rule making agencies.

Now it is overruled, sharing a dustbin with Roe v. Wade and other discarded precedents. Justice Neil Gorsuch, in a concurrence, writes that the court has placed “a tombstone on Chevron no one can miss. In doing so, the Court returns judges to interpretive rules that have guided federal courts since the Nation’s founding.” The majority opinion was written by Chief Justice Roberts.

The high court consolidated two cases — Loper Bright Enterprises v. Raimondo and Relentless v. Department of Commerce — to issue a single opinion. They both concerned the fishing of herring in the Atlantic Ocean. A 1976 law dictated that such expeditions be supervised, and a 2020 rule put a $700 price tag on such monitoring. Two circuit courts cited Chevron in turning aside the fishermen’s challenge to that fee. Justice Ketanji Brown Jackson heard one of those cases, so recused herself here.

Chief Justice Roberts, writing for his conservative colleagues, calls Chevron  “fundamentally misguided” and “unworkable.” He finds it to have been underpinned by “fiction.” Chief Justice Clarence Thomas, in his own concurrence, argues that Chevron “curbs the judicial power afforded to courts, and simultaneously expands agencies’ executive power beyond constitutional limits.” He reckons that these effects amount to “constitutional defects.”

The Chief was careful to note that the discarding of Chevron does not retroactively undo the thousands of cases over the last 40 years that have been decided on its basis. The end of deference to agencies, though, could ripple through any future rulemaking from, say, the Environmental Protection Agency, the Treasury Department, and the Internal Revenue Service.    

Justice Elena Kagan wrote the liberal wing’s dissent. She reminds the majority that Chevron “has become part of the warp and woof of modern government, supporting regulatory efforts of all kinds — to name a few, keeping air and water clean, food and drugs safe, and financial markets honest.” She adds that “the rule is right. This Court has long understood Chevron deference to reflect what Congress would want.”

The dissent argues that “shifting views about the worth of regulatory actors and their work do not justify overhauling a cornerstone of administrative law. “ In an acknowledgement, though, of the impotence of liberals on the court, Justice Kagan writes that her “own dissents to this Court’s reversals of settled law—by now fill a small volume.”