Chevron deference is a doctrine of administrative law, derived from the U.S. Supreme Court's decision in Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984). Chevron is best known for the principle that, when a statute is ambiguous and falls within the subject-matter jurisdiction of a federal agency, the agency's official interpretation of the statute, if reasonable, is the last word on the subject. This practise of allowing the agency to say what the law is is known as "Chevron deference."

While Chevron deference has certain practical advantages, such as shifting the primary responsibility for construing the statutes for which an agency is responsible from overworked, underequipped federal judges to overworked, underequipped federal administrative law judges ("ALJs"), it also creates certain problems. The entire reason that agency interpretations receive any deference is because specialised agencies are presumed to have greater subject-matter expertise than generalist judges. However, often agency behaviour goes far to rebut this presumption. One particularly good example of an agency's rebuttal of the presumption of expertise is the INS. As the legendary Judge Richard Posner of the U.S. Court of Appeals for the Seventh Circuit has noted:

The proceedings of the Immigration and Naturalization Service are notorious for delay, and the opinions rendered by its judicial officers, including the members of the Board of Immigration Appeals, often flunk minimum standards of adjudicative rationality. The lodgment of this troubled Service in the Department of Justice of a nation that was built by immigrants and continues to be enriched by a flow of immigration is an irony that should not escape notice. We imagine that Congress is more to blame than the Department or even the INS itself. The agency is absurdly understaffed. In 1994, when it decided the Salamedas' appeal from the decision by the immigration judge to deport them, the Board of Immigration Appeals had an effective membership of only four--to handle the more than 14,000 appeals lodged with the Board that year.

Salameda v. INS, 70 F.3d 447, 449 (7th Cir. 1995) Thus, frequently Chevron deference is a matter of letting the inmates run the asylum.