Decisions the EU took in response to Russia's 2022 invasion of Ukraine have been assessed in scholarship as ‘unprecedented’ and ‘unthinkable before’. The Union's response to the 2022 full‐scale invasion has thus been much stronger than the one linked to the annexation of Crimea in 2014. The difference between the 2014 and 2022 responses can be attributed to many factors, particularly differences in the nature and scale of Russia's attacks and the US co‐ordination efforts during the Russian pre‐war military mobilization on Ukraine's borders. We show that, though these factors undoubtedly matter, it has been the path‐dependent dynamics of EU–Ukraine co‐operation on association relations, Ukraine's resilience‐building and the EU's socialization with Ukraine from the Euromaidan Revolution (2013‐14) to the 2022 invasion that contributed to the strength and promptness of the EU's response to Russia's full‐scale invasion.