The Chevron doctrine, which says that when agency interpretations of laws that they administer are challenged in federal court, the court isn't supposed to figure out the right answer to the question of statutory interpretation. It's supposed to look for a clear answer, and if there isn't a clear answer, you approve the agency decision as long as it's reasonable. That's been one of the most controverted doctrines of administrative law over the last three and a half decades, even during a time in which it's been the dominant approach in that respect. What do I mean by all of that? Well, a lot of the opposition to Chevron from the moment that the doctrine was first developed by the lower courts through today has focused on what it is the judges are supposed to do. What judges are supposed to be good at is figuring out what the law means. Why would you allocate decision-making authority on that matter to agencies rather than courts? It doesn't make any sense. That argument has been around for a very long time. The counter to that is, well, that might be true if what was going on in these administrative cases is the interpretation of statutes. But it's not. It looks like the interpretation of statutes. There are these words written down in the United States code, and the agency is mouthing things that involve those words in the United States code, but those things in the United States code aren't really functioning as statutes in the sense of creating legal rights and obligations. They're delegations. Sub-delegations. They're authorizations to the agency to go forth and do good, to make policy. If you're choosing between the agencies and the courts as policy makers, well, the agencies have both an expertise and a democratic pedigree that the courts don't have. So a lot of the arguments about the wisdom or validity of Chevron turn on very, very deep questions about what exactly is going on when agencies intone the language of statutes and you have to decide, in a world without a non-delegation doctrine, are those statutes really creating law or are they creating law givers, charging the agencies with making the policy? Because these issues involve deep questions of jurisprudence, that's part of why they have been so controversial.