This book is a major intervention into just war theory by the most influential contemporary interpreter and exponent of Kant''s legal and political philosophy. Building on Kantian foundations, it offers a reconceptualization of the duties of the state and the norms governing war. Ripstein argues that a special morality governs war because of its distinctive immorality: The wrongfulness of entering or remaining in a condition in which force decides everything provides the standards for evaluating the grounds of initiating war, the ways in which wars may be fought, and the results of past wars.