For the last couple years, I have been digging into some history that sheds new light on the creation of the American administrative state. The research grew out of work on the Supreme Court’s Chevron doctrine, which requires courts to defer to reasonable agency interpretations of statutes. In two recent decisions, Christensen and Mead, the Court cut back on Chevron, saying that it applies only to agency interpretations that have the “force of law.” In order for agency interpretations have the force of law, the Court explained, Congress must delegate authority to the agency to act with the force of law.