There is an apparent paradox in Ireland’s relationship with the European Union. On the one hand, Ireland’s political system is marked by a “fundamental nationalist consensus” (Garvin 2005: 3; see also Boyce 1995; English 2006; Mays 2007). On the other hand, Ireland is also regularly portrayed as being “at the heart of Europe” (various recent uses of this phrase are sourced in Holmes & Simpson 2021: 1), the very paragon of pro-integration sentiment and ‘good Europeanness’. Of course, both views are simplifications. But both also capture something of a reality. Nationalism is a powerful factor in Irish politics, but so is support for European integration. This paper will analyse this apparently contradictory stance, and will argue that in fact the Irish model illustrates the potential for nationalism and integration to co-exist. Key to this on the Irish side has been the move away from absolutist conceptions of national sovereignty to an emphasis on effective sovereignty, stressing an adaptive approach to nationalism. On the EU side, an acceptance of the principle of subsidiarity and a judicious vagueness about certain potentially controversial topics have helped to make this work.