This article explores the normative international relations theory of Mervyn Frost.Frost's unorthodox approach to questions of human rights offers a way through the politicaland philosophical morass that has often threatened to obscure the most pressing issues of ourtime. Significantly, Frost claims to able to ‘construct’ a background justification forinternational ethics that can unite the demands for sovereign autonomy with declarations ofhuman rights. In doing so Frost attempts to offer an new understanding of universal ethicsand thus of the role of human rights in international politics. Acknowledging the importanceof this approach, this article examines two issues that arise from Frost's ‘constitutive theory’and seeks to offer a signpost for the future development of human rights theory.