Margaret Jane Radin’s personality theory of ownership posits that property that is bound up with the identity of its holder deserves the highest level of protection, so long as there is an objective moral consensus that the holder’s attachment to the property is healthy. In recent years scholars have relied on Radin’s theory to claim that objects like the Parthenon Marbles are so tied to the identity of a particular cultural community that group ownership of them is justified. Furthermore, they argue that the group whose identity is bound up with an object has a stronger claim to it than a rival with no such connection or a rival whose connection has been deemed unhealthy by an objective moral consensus. Yet neither Radin nor scholars extending her theory to the cultural property context have explained how to determine when such an objective moral consensus exists. This Note argues that jus cogens norms of customary international law should be considered a source of “objective moral consensus” for the purpose of distinguishing healthy from unhealthy group property claims under Radin’s theory. Jus cogens norms are valued by so many people across different cultures that there is an objective moral consensus—or the closest thing to it—that violating them is wrong. If an object is bound up with the identity of a cultural group in a way that violates one of these norms, promotes practices that violate one of these norms, or purposefully expresses adherence to contrary beliefs, then that claim to the property is unhealthy and should not be protected against the healthy claims of other groups.