The archetype of the New Deal agency, exercising neutral, technocratic expertise, is no longer tenable. As Richard Stewart (1975) noted thirty-five years ago, administrative law “is undergoing a fundamental transformation.” Following Stewart, the modern explanation in legal scholarship of the transformation is that federal judges came to the rescue of the administrative state, actively intervening in the regulatory process in order to preserve key values which had been threatened by an admixture of internal pathologies and external (read: “political”) threats. We argue that the traditional explanation neglects a central aspect of the major transformations in American regulatory politics during the past half century – the critical role of Congress and the President in the reformation of both the American regulatory state and administrative law. The traditional explanation in legal scholarship, that courts implemented values and agendas separate from legislative aims, and hence separate from politics, is flawed because it neglects the larger transformations, beginning in the 1960s and continuing over the next two decades, in American national politics. During this period, a wide range of new constituencies arose, including the environmentalists, consumerists. The courts’ role in the reformation must be seen in this broader political transformation of the 1960s and 70s rather than in a court-centric perspective in isolation from the rest of the political system. We illustrate our thesis with nuclear power regulation, which demonstrates the critical, joint roles of entrepreneurs in Congress and the courts.