Chevron Deference

What Chevron Deference Was

Chevron deference was a rule that told federal courts to defer to a government agency’s reasonable interpretation of an unclear law that the agency administers. If Congress wrote an ambiguous statute, judges were supposed to accept the agency’s reasonable reading rather than substitute their own. The Supreme Court created the rule in 1984 and overruled it in 2024, so courts now decide for themselves what an ambiguous federal law means.

The practical meaning was that on unclear laws, the expert agency, not the judge, usually had the last word. A specialist at the EPA who read an ambiguous clean-air statute one reasonable way would win, even if the judge would have read it another way. That is what changed in 2024.

How the Two-Step Test Worked

The doctrine ran on a two-step test that decided when a court had to defer. First the court asked whether Congress had already answered the question in plain text. Only if the statute was genuinely unclear did the court move to the second question, where the agency usually won.

That second step is where most of the fights happened, because “reasonable” let agencies fill gaps Congress left. Over time the Court added limits that narrowed when Step 2 even applied. Mead (2001) added a threshold “Step Zero,” so only formal agency action qualified for deference. The major questions doctrine from West Virginia v. EPA (2022) carved out agency decisions of “vast economic and political significance,” which courts would not let an agency claim from a vague statute. The weaker fallback was Skidmore deference (1944), which gave an agency’s view only the weight of its “power to persuade.”

Why It Mattered Across Government

Chevron reached nearly every federal agency, which is why overruling it touched the whole government at once. The agencies that write the rules Americans live under all worked in its shadow.

For 40 years the doctrine shaped how courts reviewed the EPA, FDA, SEC, NLRB, IRS, and more. It decided EPA air and water rules, FDA drug approvals, FCC net-neutrality rules that were repealed and restored across administrations under the same statute, OSHA workplace-safety rules, and immigration-board decisions. When a rule was challenged, Chevron was often the difference between the agency winning and losing.

How the Doctrine Was Made and Unmade

The arc runs from a unanimous 1984 decision that created the two-step test, through Mead in 2001 and Massachusetts v. EPA in 2007, the King v. Burwell sidestep in 2015, the major questions doctrine crystallized in West Virginia v. EPA in 2022, to Loper Bright overruling Chevron in 2024 and Corner Post restarting the challenge clock that same summer.

1. 1984 Chevron creates the test Justice Stevens writes a 6-0 opinion (three justices not participating) upholding an EPA clean-air rule and setting up the two-step test.
2. 2001 Mead adds Step Zero The Court limits Chevron to formal agency action, a threshold before deference applies.
3. 2007 Court polices major calls Massachusetts v. EPA signals courts will scrutinize the biggest agency decisions.
4. 2015 King v. Burwell sidesteps On a question of vast significance, the Court interprets the statute itself instead of deferring.
5. 2022 Major questions doctrine West Virginia v. EPA carves out decisions of vast economic and political significance.
6. 2024 Loper Bright overrules Chevron The Court ends Chevron 6-3 and puts statutory interpretation back with judges.
7. 2024 Corner Post restarts the clock The six-year challenge clock runs from a plaintiff injury, reopening old rules.

Sources: Justia; supremecourt.gov; CRS R44954.

From the 1984 two-step test to the 2024 overruling: 1984 — Chevron creates the test (Justice Stevens writes a 6-0 opinion (three justices not participating) upholding an EPA clean-air rule and setting up the two-step test.). 2001 — Mead adds Step Zero (The Court limits Chevron to formal agency action, a threshold before deference applies.). 2007 — Court polices major calls (Massachusetts v. EPA signals courts will scrutinize the biggest agency decisions.). 2015 — King v. Burwell sidesteps (On a question of vast significance, the Court interprets the statute itself instead of deferring.). 2022 — Major questions doctrine (West Virginia v. EPA carves out decisions of vast economic and political significance.). 2024 — Loper Bright overrules Chevron (The Court ends Chevron 6-3 and puts statutory interpretation back with judges.). 2024 — Corner Post restarts the clock (The six-year challenge clock runs from a plaintiff injury, reopening old rules.).

1984: Justice Stevens wrote the Supreme Court opinion in Chevron v. NRDC, decided 6-0 by the participating justices (three took no part), upholding an EPA “bubble” rule under the Clean Air Act and creating the two-step test. Stevens later said he thought he was restating existing practice, not revolutionizing it.

2001: In United States v. Mead Corp. the Court added “Step Zero,” holding that only formal agency action carrying the force of law qualified for Chevron deference.

2007: In Massachusetts v. EPA the Court showed it would police major agency calls rather than rubber-stamp them.

2015: In King v. Burwell the Court sidestepped Chevron on an Affordable Care Act question it called too significant to leave to agency interpretation.

2022: In West Virginia v. EPA the Court crystallized the major questions doctrine, holding that agencies need clear congressional authorization for decisions of vast economic and political significance.

2024: In Loper Bright v. Raimondo the Court overruled Chevron 6-3, the culmination of a long campaign by Justices Gorsuch and Thomas and the scholar Philip Hamburger, who argued on Article III and Administrative Procedure Act grounds that interpreting law is the courts’ job.

2024: In Corner Post v. Board of Governors the Court held the six-year clock to challenge a rule runs from when a plaintiff is first injured, reopening decades-old rules to fresh lawsuits.

What Loper Bright Decided

The case that ended Chevron started with herring fishermen, not a sweeping legal theory. A group of Atlantic herring fishermen, including the New Jersey company Loper Bright Enterprises, challenged a National Marine Fisheries Service rule that made them pay for the at-sea monitors riding on their own boats.

The fee ran about $700 a day, up to roughly 20% of a boat’s revenue, and the fishermen argued the agency had no clear authority to charge them for it. The Supreme Court used their case to decide a much larger question about who interprets unclear law.

On June 28, 2024, in a 6-3 decision by Chief Justice Roberts, the Court overruled Chevron. It held that the Administrative Procedure Act requires judges to “decide all relevant questions of law” and exercise independent judgment, and it leaned on Marbury v. Madison for the principle that interpretation is the judiciary’s duty. Justice Jackson was recused from Loper Bright and joined the dissent in the companion case, Relentless, Inc. v. Department of Commerce.

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

Marbury v. Madison, quoted by Chief Justice John Roberts in Loper Bright v. Raimondo, 2024

What replaced Chevron is independent judgment. Courts now interpret ambiguous statutes themselves and may give an agency’s view weight only under Skidmore, where it counts if it persuades. The Court preserved prior rulings that had relied on Chevron, so those specific holdings did not automatically reverse. Days later, Corner Post changed who could sue and when.

That ruling means a newly formed or newly affected business can now challenge a rule that has been on the books for decades, because the clock starts when the plaintiff is first injured rather than when the rule was issued.

What Has Changed Since 2024

Courts began citing Loper Bright to strike agency rules within months. As of June 2026, a federal court vacated the Department of Labor’s overtime “white-collar” rule in November 2024 citing Loper Bright, and the Fifth Circuit struck a Department of Labor tip-credit rule in 2024. A court used Loper Bright to strike a Department of Education Title IX rule in Tennessee v. Cardona in 2025, and the EPA moved to roll back chemical-accident Risk Management Plan rules in 2025 and 2026.

Not every rule fell. Courts have upheld agency rules where the statute clearly authorized the action. The pattern is that clearly authorized rules hold while rules built on ambiguous text are now exposed.

Why It Matters

The change decides who has the last word on what an unclear law means. Before Loper Bright, that word usually belonged to expert agencies answerable to an elected president. Now it belongs to generalist judges with lifetime tenure.

The shift is real, but it is not total. Agencies still get deference on technical fact-finding, because arbitrary-and-capricious review under the State Farm standard survives. Congress can still write clear statutes, and it can legislate deference back where expertise matters. And because courts now set a single reading rather than each administration flipping the interpretation, some rules may become more stable over time.

The Honest Disagreement

Serious people disagreed about whether Chevron should have survived, and the disagreement is worth stating fairly. The two sides split over a single question: who should resolve a genuine ambiguity in the law, the expert agency or the court.

The case for deference came from Justice Kagan’s dissent and scholars like Cass Sunstein. They argued that agencies employ the scientists and economists who understand the technical questions, that agencies answer to an elected president while judges do not, that one agency reading keeps the law uniform across the country, and that Congress often delegates gap-filling on purpose. Kagan called the majority’s move a shift from a rule of judicial humility to one of judicial hubris.

A rule of judicial humility gives way to a rule of judicial hubris.

Justice Elena Kagan, dissenting in Loper Bright v. Raimondo, 2024

The case against Chevron came from the Loper Bright majority, Justices Gorsuch and Thomas, and the scholar Philip Hamburger. They argued that Article III and Marbury make saying what the law is the courts’ job, that the Administrative Procedure Act tells courts to decide all relevant questions of law themselves, and that deference let agencies flip their readings between administrations and tilted close cases toward the government.

The honest distinctions sit between those positions. Deference to scientific fact-finding stays strong under State Farm review, while deference on pure legal interpretation ended. Genuine ambiguity is different from agency overreach. Stability across administrations trades against flexibility to update old rules. Expertise weighs against constitutional accountability. And one national agency reading guards against the risk of conflicting circuit rulings. We do not declare a winner on these close calls.

Frequently asked questions

Is Chevron deference still law? No. The Supreme Court overruled it in Loper Bright v. Raimondo on June 28, 2024.

Does this mean agencies get no deference at all? Not quite. Courts decide legal questions themselves, but they may still credit an agency’s view under Skidmore when it persuades, and they still defer to agency fact-finding under arbitrary-and-capricious review.

Are old regulations now void? No. Prior rulings that relied on Chevron still stand. But Corner Post lets newly injured parties challenge old rules going forward.

Who decides what an ambiguous law means now? Federal courts, exercising independent judgment.

What you can do

1. Ask Congress to write clear laws and to legislate deference back where expertise matters. Support legislation to codify agency deference and require agencies to weigh public input, modeled on the Stop Corporate Capture Act, so health, safety, and environmental rules do not turn on each judge’s reading. Use the letter and call script below.

2. Ask your members of Congress where they stand on agency power after Loper Bright. Get a clear, on-the-record answer on whether they want expert agencies or generalist judges deciding what unclear health and safety laws mean.

3. Learn the related law so you cannot be misled. Read the executive orders explainer on how agencies make policy and the judicial review explainer on the courts’ power to interpret law.

4. Watch the rules that affect you. Clean-air, drug-safety, overtime, and workplace rules are being relitigated after Loper Bright. Follow the agencies that set them and the lawsuits challenging them.

5. Write your representative using the letter below and ask for a clear position on agency authority.