Among the folks who work in the federal government, or who practice administrative law, Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc. (1984) is a very famous case, indeed. It's a little weedy, but here's the Cliff's Notes version:
In its decision, which was technically unanimous (though three sitting justices did not participate at all), the Court ruled thusly:
First, always, is the question whether Congress has directly spoken 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, however, the court determines Congress has not directly addressed the precise question at issue, the court does not simply impose its own construction on the statute... Rather, if the statute is silent or ambiguous with respect to the specific issue, the question for the court is whether the agency's answer is based on a permissible construction of the statute.
In other words, if a statute doesn't spell things out clearly for a federal agency, then the agency is allowed to use its best judgment, as long as its conclusions are within reason. This is known as the Chevron doctrine, or as Chevron deference.
Now, the Chevron doctrine could be the latest thing to end up on the current Supreme Court's chopping block. Chief Justice John Roberts & Co. have agreed to hear Loper Bright Enterprises vs. Gina Raimondo, which is even weedier than the original Chevron case. In short, Loper Bright thinks that the National Marine Fisheries Service overstepped its bounds when interpreting the Magnuson-Stevens Fishery Conservation and Management Act. Frankly, if we had a nickel for every time we've gotten into an argument over the terms of the Magnuson-Stevens Fishery Conservation and Management Act... well, in any case, if Loper Bright wins, SCOTUS could very well do away with the Chevron doctrine altogether.
On the whole, this is being framed as a Republicans vs. Democrats issue, since the former dislikes government power and wants to see the agencies' wings clipped, while the latter likes government power just fine, and wants to see the agencies spread their wings. However, that's probably not the best way to think about it. The Chevron doctrine has effectively given more power to the executive branch, somewhat at the expense of the legislative branch. Whether you think that's a good thing probably depends on what the executive branch is trying to do at that particular time. The original Chevron case involved a conservative president using ambiguities in the law to advance conservative environmental policies. So, it can certainly cut both ways.
It is also worth noting that Chevron doctrine cases are already something of a coin flip. Depending on whose study you believe, the federal bureaucracy's interpretations of ambiguous laws are sustained between 55% and 70% of the time. So, even if SCOTUS gets rid of Chevron deference, it's not a completely radical departure the way that, say, the Dobbs decision was.
Of course, the first "victim" of the decision, if SCOTUS does kill Chevron deference, will be Joe Biden. In particular, given that getting environmental legislation through Congress right now is roughly as easy as passing a kidney stone, the administration depends on "interpretations" of existing statutes in order to implement its environmental agenda. So, the impact could be quite profound, even if the decision flies below the radar. (Z)