This article critically assesses Michael Kirby’s interpretive principle [that the Constitution should be interpreted, so far as is possible, consistently with principles of international law, and especially principles of international human rights law] to reveal the assumptions underlying it and suggests that the principle is not really about international law but rather about moral claims regarding human dignity and the role of the judge. The article proceeds in three main parts. First, the interpretive principle is articulated, its different forms noted and its limitations considered. Secondly, the article reﬂects upon what the interpretive principle reveals about how Kirby sees the role of the judge and how this informs the interpretive principle. Finally, the article considers the emphasis Kirby places on human rights values and how international law ﬁts into the interpretive principle.