This dissertation develops a Kantian philosophical framework for understanding our individual obligations under public law. Because we have a right to do anything that is not wrong, the best interpretation of Immanuel Kant's Universal Principle of Right tracks the two ways--material and formal--in which actions can be wrong. This interpretation yields surprising insights, most notably a novel formulation of Kant's standard for formal wrongdoing. Because the wrong-making property of a formally wrong action does not depend on whether or not the action in question has been prohibited by statute, Kant's legal philosophy is consistent with a natural law theory of public crime. Moreover, because the law can obligate us only by establishing a univ...