Drawing conceptual boundaries is one of the defining features of constitution-making processes. These historically situated operations of boundary making are central to the definition of what counts as "constitutional" in a political community. In this article, we study the operations of conceptual delimitation performed by the Constitutional Commission (1973-1978) that drafted the 1980 Chilean Constitution, the trademark of Augusto Pinochet's dictatorship. Using the eleven volumes of the Commission's Official Records as our textual material (10,915 pages and 80,005 distinct words), we apply vector semantics, spectral clustering and bigram graph-based analysis to explore conceptual boundaries and the behavior of specific keywords shaping the space of constitutional meanings. Our results identify the ways in which the Commission defines the normative horizon of the new social and political order by transforming old semantic references into a renewed conceptual framework. This analysis shows the immanent relations between political action and conceptual elaboration that underlie the creation of constitutional texts, as well as the potential of computational methods for the study of constitutional history and constitution-making processes.