Administrative and Executive agencies make rules all the time and have done so from the get go. So for example, they can establish rules for the conduct of their own officers and the organization of their agency and so on and so forth. Those kinds of rules aren't particularly problematic. They also issue rules, however, with binding legal force in ways that restrict private conduct and may restrict the exercise of private rights and it's those rules with binding force that pose delegation or non delegation problems, to what extent must Congress make those rules on its own. Congress can leave the minutiae to an agency that is to say, if this is really sort of a matter of defining what exactly is a smoke stack, and what is a chimney, Congress cannot realistically, make that decision on its own. It's perfectly okay to delegate that to an agency. Once you're dealing with rules that are much more contestable, affect a whole lot more people, restrict private liberty or private rights to a greater extent, you do have a serious problem. Over time, the Court migrated to something that's called an intelligible principle. And what it says, what the doctrine says, is that so long as Congress has stated an intelligible principle to guide the agency; intelligible, that is to the public, to Congress itself, to the reviewing courts, to the agency. So long as there's an intelligible principle, the delegation of what looks like law making power is okay. And it has turned out that just about everything and anything is intelligible or has proven intelligible to the courts. So that principle really has no bite. No independent force at all. In recent cases, several of the justices led by Justice Gorsuch and by Justice Thomas have questioned that understanding of the doctrine and insisted that the court should return to something more, like its traditional understanding of the doctrines. For now, these opinions have come mostly in the form of dissents in some quite important cases, but there's perennial speculation that one of these days, the Supreme Court will find five or six votes, to invalidate a statute on non delegation grounds. Meanwhile, the non delegation doctrine, and this is important, has lived a very active life not as a direct constraint on the Congress, but as a mode of interpreting federal statutes. So for example, the Court has said in repeated cases that if we were to read the statute in the expansive way, the agency wants us to read it, then we would have a serious, or might have a serious delegation problem. Therefore, we will read the statute in a more restrictive fashion. That's called a Constitutional Avoidance Canon. And the other canon that has played a significant role here is something called the Major Question Doctrine. That is to say, if the activity that the agency proposes to undertake under this ambiguous statute is so big and so politically consequential, that a whole lot is at stake, we, the Court, will no longer accept the agency's interpretation of the statute. We will not presume that Congress meant to delegate that authority to the agency. And so therefore we will read the statute in a much more restrictive fashion.