The article addresses dynamics of conceptual space and communicative organization of the American political discourse in the 20 th – early 21 st centuries. The research objective is to identify transformations in the content of universal and nationally-marked concepts, as well as verbal modification of communicative strategies and tactics in the American political discourse of the periods under study. The main research methods applied are discourse, conceptual, semantic, and contextual analysis. The sampling corpus incorporates 662 public speeches of American presidents. The speeches under analysis belong to the ritual, orientational, and agonal genres of the political discourse. The main discourse-forming and nationally-marked concepts, features of the communicative structure of the American political discourse are established. The analysis of the metaphorical system as a way of realizing the intention in the American political discourse is carried out. The main types of conceptual metaphor, representing the discourse-forming concepts of the American political discourse are considered. The American political discourse conceptual space is more prone to transformations than its communicative structure in the studied timeframe. The nationally-marked concepts tend to be more dynamic than the universal discourse-forming concepts. The conceptual dynamism of the nationally-marked concepts manifests itself in the prevalence of the dominant features and the lacunarity at different stages of the American linguo-cultural community existence. The nationally-marked concepts components related to the historical and socio-cultural aspects of the speaking community life are brought into the open in the speeches of American presidents as transmitters of the national cultural values and role-status configurations in the political discourse of the 20 th – early 21 st centuries.