"It is emphatically the province and duty of the judicial department to say what the law is."

In 1984, the Supreme Court decided Chevron U.S.A. v. Natural Resources Defense Council. The ruling established a two-step framework: if Congress passed a statute with an ambiguous term, courts would first ask whether Congress had directly addressed the question. If not, courts would defer to whatever the agency said the ambiguous term meant — as long as the agency's interpretation was "reasonable."

The practical result was a 40-year transfer of interpretive power from courts to agencies. When an agency wanted to expand its authority, it needed only to find an ambiguous word in its enabling statute and declare that the ambiguity authorized the expansion. Courts would defer. The EPA used "navigable waters" to regulate isolated ponds. OSHA used "occupational safety" to mandate vaccines for 84 million workers. The ATF used "machinegun" to ban bump stocks. The CFPB used "unfair" to impose sweeping lending restrictions.

This was not what the Constitution established. Article I, §1 vests all legislative power in Congress — not in agencies. Article III vests the judicial power — including the power to say what the law means — in courts, not agencies. Chevron deference inverted both of these constitutional assignments simultaneously.

The case arose from a mundane dispute: the National Marine Fisheries Service (NMFS) required Atlantic herring fishing vessels to carry federal monitors aboard — and to pay the monitors' $700-per-day salaries out of their own revenue. The fishing company, Loper Bright Enterprises, challenged the cost-shifting requirement. NMFS pointed to a provision of the Magnuson-Stevens Act authorizing it to "require" observers. The question was whether "require" authorized cost-shifting.

The Court, in a 6-3 opinion by Chief Justice Roberts, held that it did not — and went further, overruling Chevron entirely. The Roberts opinion rested on three pillars:

"Courts must exercise their own independent judgment in determining the meaning of statutory provisions. Courts may not defer to an agency interpretation of the law simply because a statute is ambiguous."

The Court was careful to note that prior decisions issued under Chevron are not automatically overturned — the doctrine of stare decisis still applies to specific holdings. But going forward, no court may defer to an agency's interpretation of an ambiguous statute simply because the agency finds the ambiguity convenient.

Loper Bright is not an isolated administrative law ruling. It is the Supreme Court's most direct affirmation in 40 years of the structural principle that runs through every module on this platform: the separation of powers is not a suggestion. When one branch exceeds its constitutional authority, the other branches have not only the power but the obligation to say so.

Loper Bright is not merely an academic ruling. It is an actionable tool for anyone facing a federal agency rule that exceeds the agency's statutory authority. The six-step challenge framework below applies to any federal regulation you believe was issued without clear congressional authorization.