The Constitution makes Congress the principal federal lawmaker. But for a variety of reasons, including partisan gridlock, Congress increasingly fails to keep up with the challenges facing our society. Power has shifted to the executive branch agencies that interpret laws and to the courts that review their interpretations.

Since the Supreme Court's 1984 decision in Chevron v. Natural Resources Defense Council, this judicial review has been highly deferential: courts must uphold agency interpretations of unclear laws so long as these are "reasonable." But the Chevron doctrine faces backlash from constitutional scholars and, now, from Supreme Court justices who insist that courts, not administrative agencies, have the authority to say what the law is. Critics of the administrative state charge that Chevron deference enables unaccountable bureaucratic power. In this groundbreaking book, Thomas Merrill reviews the history and consequences of the Chevron doctrine and suggests a way forward.