 Sure. Let's go back before Chevron just a bit. For years, the court had struggled with how should we look at agency actions? How much deference should we give to what the agency is saying? And so there's this sort of amorphous test where the court would say, well, we should give some weight to what the agency thought. Chevron, a unanimous decision in 1984, said, hey, let's make this clear. When an agency interprets an ambiguous law,