Our constitutional jurisprudence is in large measure built around the concept of guarding against arbitrary governmental action. But in an age of increasing legislative dysfunction, a more pronounced threat may be arbitrary congressional inaction. Individual members of Congress block majorities from voting on key legislation, and a single senator may prevent votes on executive and judicial branch nominations through the use of holds and other tactics. This form of congressional inaction not only poses a threat to many framework principles such as legislative supremacy, democratic accountability, and separation of powers, but also embodies the very concerns over arbitrary government that form the basis of over two hundred years of judicial review. For these reasons, this Article advances a novel, and undoubtedly contentious argument: federal courts should review certain types of congressional inaction for arbitrariness. To overcome the skepticism likely to greet the proposal, the Article establishes the solid historical and analytic foundations for such review before undertaking the step of explaining how it might work in practice.