Constitutional unamendability has recently found justifications that show reverence to constituent power. Such justifications ascribe natural unamendability to the fundamental principles based on democratic founding. These accounts overlook the point of having a constitution and the values that make up constitutionality. In grounding unamendability, they wrongly take constituent power instead of constitutionality as their point of reference. This paper argues that ascribing constitutionality to a polity is already to elevate it with a certain character. A justification for constitutional unamendability must therefore address directly the inevitable step of evaluation in making sense of the concept of constitutionality. This paper draws on Fuller’s distinction of moralities of duty and aspiration and Finnis’s concept of focal meaning to articulate constitutionality as an aspirational ideal and constitutional unamendability as a tool to realise constitutionality’s morality of duty.