Political theorists, especially in the subfield of ideology studies, continue to draw insights from Begriffsgeschichte (conceptual history) to help them better analyze the morphology of political concepts over time. However, other aspects of Reinhart Koselleck’s work remain underutilized. This is especially true of the connections between Begriffsgeschichte and his development of a theory of history (Historik), dealing with the broader intersection of language, structure, and the experience of time. This article focuses on just one aspect of this intersection: on the potential relevance of Koselleck’s use of the concept of horizon to theorize a particular “horizonal mode” of the politics of time. After discussing some relevant features of the horizon metaphor, the article moves to reappraise Koselleck’s use of the concept before elaborating and expanding on it to claim that Koselleck helps to showcase the contestation of different temporal horizons as a core feature of political thinking.