In recent years, several judges on the nation’s most important regulatory court—the United States Court of Appeals for the District of Columbia Circuit— have given birth to libertarian administrative law in the form of a series of judgemade doctrines that are designed to protect private ordering from national regulatory intrusion. These doctrines involve nondelegation principles, protection of commercial speech, procedures governing interpretive rules, arbitrariness review, standing, and reviewability. Libertarian administrative law, which has a long tradition, can be seen as a second-best option for those who believe, as some of the relevant judges openly argue, that the New Deal and the modern regulatory state suffer from basic constitutional infirmities. Taken as a whole, libertarian administrative law parallels the kind of progressive administrative law that the same court created in the 1970s and that the Supreme Court unanimously rejected in Vermont Yankee. It should meet a similar fate.