Many people vigorously defend particular institutional judgments on such issues as the filibuster, recess appointments, executive, privilege, federalism, and the role of courts. Though these judgments are defended with great intensity and conviction, some of them turn out to be exceedingly fragile, in the sense that their advocates are prepared to change their positions as soon as their ideological commitments cut in the other direction.In this Article, Professors Posner and Sunstein argue that these “institutional flip-flops” are a product of “merits bias,” a form of motivated reasoning through which short-term political commitments make complex and controversial institutional judgments seem self-evident (thus rendering those judgments vulnerable when short-term political commitments cut the other way). The authors then offer survey evidence to support the claim that merits bias plays a significant role. They then suggest that institutional flip-flops may be a result of compromise within multimember groups or may be a result of learning, as, for example, when a period of experience wit ha powerful president or Supreme Court leads people to favor constraints. Professors Posner and Sunstein then propose solutions for reducing the number and degree of institutional flip flops that political actors engage in, and explore the potential problems with their proposed solutions and how they might be overcome.