Federal agencies have broad and deep influence over our lives. How far, though, can they go before a court will stop them? The answer is in the rule of the case of Chevron U.S.A. v. Natural Resources Defense Council, 467 U.S. 837 (1984), written by Associate Justice John Paul Stevens which says:
“First, always, is the question whether Congress has spoken directly to the precise question at issue. If the intent of Congress is clear, that is the end of the matter; for the court as well as the agency must give effect to the unambiguously expressed intent of Congress.”
“If the Court determines Congress has not directly addressed the precise question at issue, the court does not simply impose its own construction of the statute . . . Rather”“[I]f the statute is silent or ambiguous with respect to the specific question, the issue for the court is whether the agency’s answer is based on a permissible construction of the statute.
467 U.S. 637, 842-843 (1984).
In this case, the NRDC had objected to some Environmental Protection Agency regs, having won at trial, Chevron, affected by them, appealed and the case ended up with the Supremes.
United States Supreme Court opinions commonly refer to and use this "Chevron deference."
Chevron U.S.A. v. Natural Resources Defense Council, 467 U.S. 837 (1984)