Brexit – the EU membership crisis that wasn’t?

This introduction to the special issue recalls the alarm raised in EU capitals and Brussels after the UK's in-out referendum delivered a Leave vote in June 2016. The fear was of a domino effect and the further fragmentation of an already divided EU. Seven years later, it is clear that there was rapid attrition of Eurosceptic triumphalism, and the EU-27 showed remarkable unity. This required a sustained collective effort to contain a membership crisis and maintain the EU polity. Yet, the issue contributors challenge the notion that the alarm was unfounded and explain why this counter-factual did not materialise, even though potential for future membership crises of different sorts was revealed. Theoretically, this supports an understanding of the EU as a polity that is fragile, yet able to assert porous borders, exercise authority over a diverse membership, and mobilise a modicum of loyalty when the entire integration regime is under threat.