This article explores the relationship between ideology, the state and the transnational as it bears on European integration. Though typically studied in national contexts, ideologies and their clash have been Europe-wide since their emergence. As I argue, the European Union (EU) can be understood both as the continuation of these long-standing cross-border dynamics, and as the attempt to supersede them. Contemporary developments renew this dialectic. By exploring how ideology and European integration entwine, the paper underlines the value of a research agenda of heightened importance as the ideological hegemony of recent decades breaks down. 1 KEYWORDS Europe; European Union; history; ideology; politicization The emergence of political ideologies tracked the emergence of the modern state. Accepting the ambiguities of definition and causality, a temporal overlap seems clear. Isms of diagnosis and prescription tied to groups of various kinds developed with the reorganization of authority that brought the feudal period to a close. Whether in the guise of doctrines intended to legitimise new institutions, contest them in the name of self-determination, or restore the world that preceded them, ideologies came to the fore with the emerging state. Yet equally, ideologies were never likely to be constrained by state boundaries. Already in the late-eighteenth century, isms developed wider horizons, being extended to conflicts international in scope and deployed for cross-border constituencies. From the conflicts of the French Revolution to defences of empire, ideologies became transnational phenomena. It is the extension of ideologies outwards from the state that this article examines, with an eye in particular to European integration. Scholars typically approach ideology as a phenomenon of national settings, or else leave its sphere undefined (Bell, 2002, p. 224). Studies that set the likes of liberalism, socialism and conservatism in transnational context are rarer, like those of ideologies linked to transnational institutions (Martill, 2017). Where scholars look beyond the state, it is often to the global level. Steger's work on