This post summarises my recent article, 'Accommodating Territorial Contestation and National Constitutional Change: The Cases of Cyprus and Ireland', published in Irish Studies in International Affairs (Vol. 36, No. 2, 2025). I recently discussed the article with Rory Montgomery on the 50th episode of the ARINS Podcast — well worth a listen if you want to hear the arguments developed in conversation.
Born from the ruins of two world wars, the founding logic of the European Union has been simple: bind European states so closely together that conflict between them becomes unthinkable. And yet, when it comes to the most stubborn territorial disputes within its own borders such as the ones in Cyprus and Northern Ireland (while it was part of the EU) the EU has never quite managed to resolve them. What it has done, however, is something arguably more subtle: it has accommodated them.
My recent article examines how the EU has achieved this, and what it means for the future of both islands.
From peacemaker to manager
At the time of the Big-Bang Enlargement, there was a popular theory that EU integration has a 'catalytic effect' on conflict resolution — that the prospect of membership incentivises parties to reach settlements, and that the shared framework of EU law gradually dissolves the tensions that fuel disputes (Coppieters et al., 2004; Tocci, 2004; Diez et al., 2006).
Indeed, the accession process did bring Turkey and the Turkish Cypriots to the negotiating table in the early 2000s. And yet, Cyprus joined the EU in 2004 divided, after the Greek Cypriot community rejected the UN-sponsored reunification plan just days before accession. At the same time, while EU membership undoubtedly helped make the Irish border invisible in the years before Brexit, there was a question about the effect of UK’s withdrawal from the EU and its single market on Northern Ireland's post-conflict society. What the EU tried to achieve in both cases was not to resolve the respective dispute but to accommodate them.
The abandoned Nicosia Airport
The legal mechanism: extending EU law beyond EU territory
The main tool the EU has used to achieve this is the extraterritorial application of EU law — that is, extending the reach of EU rules to territories that are not, strictly speaking, within the EU's territorial scope.
In Cyprus, this was achieved through Protocol No. 10 of the 2003 Act of Accession, which suspends the application of the EU acquis in northern Cyprus while simultaneously providing a legal basis for limited trade and movement across the Green Line. The EU effectively engages with an unrecognised entity without recognising it — a form of 'engagement without recognition'.
In Northern Ireland, the mechanism is the Protocol on Ireland/Northern Ireland attached to the UK's Withdrawal Agreement, as amended by the Windsor Framework. Despite leaving the EU, Northern Ireland remains subject to significant parts of EU customs and single market law. The result is a hybrid — Northern Ireland is legally part of the UK customs territory, but EU customs legislation continues to apply there in practice. The Windsor Framework's 'green lane' and 'red lane' arrangements are the practical expression of this complexity.
Neither arrangement has resolved the underlying dispute. But both have substantially eased the frictions that those disputes create in everyday life — for trade, for movement of people, for economic stability.
Derry
What happens if the islands reunify?
This is where the argument becomes most directly relevant to contemporary political debate. Both Cyprus and Ireland face, at least in principle, the prospect of future reunification. What would EU law do with that?
In the case of Cyprus, the answer is already written into primary law. Article 4 of Protocol No. 10 provides a simplified procedure — a unanimous Council Decision — through which the EU could accommodate the terms of a settlement, even one that requires significant derogations from EU law to accommodate the agreed parameters of the settlement: a bicommunal and bizonal federation with political equality of the two main ethno-religious communities.
For Ireland, no equivalent provision exists. But the European Council made clear during the Brexit negotiations that, in accordance with international law, the entire territory of a united Ireland would automatically become part of the EU. The precedent here is German reunification: in 1990, EU law was extended to East Germany through secondary legislation, without any amendment to the Treaties. A similar pathway would likely be available for a united Ireland.
The EU has the toolbox — the rest is politics
Overall, the EU legal order is flexible enough to accommodate the reunification of either island, should the people living there choose it. The legal mechanisms exist; the institutional imagination is there. None of this, of course, makes reunification more or less likely — that depends on political conditions, democratic choices, and the slow work of building trust between communities. What it does mean is that EU law need not be an obstacle. The toolbox is ready. It is up to the communities themselves to decide whether, and when, to use it.
Read the full article, open access, here. Listen to my conversation with Rory Montgomery on the ARINS Podcast here. The ARINS project — a joint initiative of the Royal Irish Academy and the Keough-Naughton Institute for Irish Studies at Notre Dame — provides evidence-based research on the most significant questions facing the island of Ireland, north and south.