Chevron, The Supreme Court, and the Law
Under Chevron deference, when an agency interprets a statute it administers (e.g., the EPA and the Clean Air Act), a court will uphold its interpretation so long as it is (generously assessed) a reasonable one, even if it is not the interpretation the court would have come up with on its own. As you might imagine, this, at least potentially, gives agencies a lot more leeway, particularly when, as is often the case, Congress has drafted the statute ambiguously.
With Chevron overturned, courts will now apply their own judgment instead of deferring to agencies. Of course, this isn t as big a deal as Larry and Norm seem to think, because Chevron has been dying the death of a thousand cuts for a while. Under the major questions doctrine, courts already decline to defer to agency interpretations where the issue has major social or economic ramifications.
So the upshot now is that if Congress wants agencies to do things, it has to tell them to. If agencies think their statutes are inadequate to their purpose, they can ask Congress to amend them. Rather than a threat to democracy, this is a modest return of decisionmaking to democratically elected legislators, and out of the hands of unelected bureaucrats.
I say modest because Chevron was dying for years, and because it was never entirely clear just how much difference it made where the rubber meets the road. Some post-Chevron studies found it made a modest difference in how often agency actions were upheld by courts post-Chevron
Glenn Reynolds.