Lexical shifts, substantive changes, and continuity in State of the Union discourse, 1790-2014

A synoptic picture of the evolution of American politics is presented, based on analysis of the corpus of presidents' State of the Union addresses, 1790-2014. The paper presents a strategy for automated text analysis that can identify meaningful categories in textual corpora that span long durées, where terms, concepts and language use changes, and evolution of topical structure is a priori unknown. Discourse streams identified as river networks reveal how change in contents masks continuity in the articulation of the major tasks of governance over US history.