["Nations and Nationalism, Volume 28, Issue 3, Page 841-860, July 2022. ", "\nAbstract\nThis article analyses the changing relevance of ethnolinguistic characteristics as predictors of political attitudes in Ukraine, drawing on surveys conducted before and after the Euromaidan revolution and Russian aggression. We argue that the usefulness of certain characteristics as measures of ethnic identity reflects their cognitive and social usefulness for the population, necessarily influenced by prevalent discourses and power relations. Our analysis focuses on the changing impact of ethnic categories on political attitudes in response to changes in social context which affect widespread perceptions of these categories among the population. We distinguish between two types of social interaction that are likely to activate ethnic identity and make it more useful for individuals' social navigation: internal differentiation and external delimitation. We hypothesize that the former type increases the relevance of ethno‐linguistic categorization while the latter facilitates ethno‐national identification. Of particular importance are two types of contextual change: International conflicts can contribute to the priority of external delimitation and, therefore, the activation of national identity, while domestic conflicts or crises can accentuate the need for internal differentiation and thus the usefulness of ethnolinguistic identity. Our analysis detects such change for certain categories of ethnic identity in Ukraine.\n"]