Long a part of the theory and practice of international politics, the principle of nonintervention has traditionally admitted few exceptions. Recently, however, arguments have been advanced that seek to expand the grounds for armed intervention to include a wide range of situations in which violations of human rights have occurred. This paper argues that although in principle the moral justification for intervention to protect human rights is broader than defenders of a strong principle of nonintervention, such as Michael Walzer, are willing to allow, the practical constraints on armed intervention are such that it can never be more than an exceptional remedy for human rights abuses.