Processes for Irish unification: Perspectives from Irish constitutional law

Professor Oran DoyleOran Doyle 191119

Editors’ Note: This post is part of an IACL-AIDC Blog Symposium on unification of the island of Ireland. The Symposium is co-hosted by the Constitution Project @ UCC Blog. Selected posts will also be co-hosted by the UKCLA Blog. The full set of posts can be found here.


International law, UK law, and Irish law adopt the same substantive position on Irish unification: it requires the consent of a majority of people in both jurisdictions on the island of Ireland. However, they approach the question from different perspectives and with subtly different emphases. In this post, I explore the issue from the perspective of Irish law to identify what unification processes would be legally effective in Ireland.

I suggest that a referendum to amend or replace the Irish Constitution is the most plausible process. I then explore how such a referendum could be integrated with processes in Northern Ireland and the United Kingdom in a way that does not reproduce the Brexit model of leaving fundamentally important choices to be made after the referendum.

This blogpost does not advocate for a united Ireland, nor for any particular form of a united Ireland.

Bare unification

The Irish Constitution of 1937 provided that the national territory consisted of the whole island of Ireland, its islands and the territorial seas. In order to give effect to the Belfast/Good Friday Agreement (GFA) 1998, several amendments were approved by referendum.

Art 3.1 now reads:

It is the firm will of the Irish Nation, in harmony and friendship, to unite all the people who share the territory of the island of Ireland, in all the diversity of their identities and traditions, recognising that a united Ireland shall be brought about only by peaceful means with the consent of a majority of the people, democratically expressed, in both jurisdictions in the island….

This establishes unification as a constitutional commitment, the realisation of which crucially requires the consent of a majority of the people, democratically expressed, north and south.

There are four ways in which consent could be democratically expressed in southern Ireland: (a) through a statute enacted by the Oireachtas (Parliament); (b) through a referendum pre-authorised by a statute to count as the democratic expression of consent; (c) through constitutional amendment by referendum; (d) through constitutional replacement by referendum. Assuming a vote for unification in Northern Ireland as well, each of these would allow extension of the national territory to encompass the entire island, subsuming Northern Ireland into the existing state.

Unification with constitutional changes

Much of the public debate on unification assumes, however, that it would be appropriate and desirable to make significant changes to the Irish state in the event of unification, principally to make it more hospitable to new citizens with a British identity. While some such changes—for example, joining the Commonwealth—could be achieved by legislation, others would require constitutional amendment or constitutional replacement. There do not appear to be any substantive limits on the power to amend the Irish Constitution. Accordingly, the choice between amendment and replacement is not legally constrained.

Among the areas where changes would, if thought appropriate, require constitutional amendment or replacement are the following:

  • Symbolic provisions of Irish nationhood, such as the national flag, Irish as the national and first official language;
  • Power-sharing arrangements in the national legislature or government;
  • Any federal or confederal system;
  • Alterations to the amendment process, whether to change the thresholds for amendment or entrench provisions against subsequent change.

It is also likely that the continuation of devolution and power-sharing in Northern Ireland would require constitutional change. While Art 15.2 allows for the establishment of subordinate legislatures, there is no equivalent provision for subordinate executives.

Although unification could take place without a referendum, it seems likely that a referendum would be preferred in order to allow at least some changes of the type just listed. How might this referendum be integrated with approval processes in Northern Ireland?

Integration of approval processes, north and south

Aoife O’Donoghue noted the GFA requirement of concurrent approvals. If both north and south approve, it is a binding obligation on the UK and Irish Governments to introduce and support in their respective parliaments legislation to give effect to that wish. Colin Murray explained how, under the Northern Ireland Act 1998, the Secretary of State is required to call a border poll in certain circumstances. If a majority in Northern Ireland then votes in favour of unification, the Act requires her to lay before the UK Parliament such proposals to give effect to that wish as may be agreed between the UK and Irish Governments.

It is these provisions that tend towards the Brexit model: referendum followed by negotiations. But if negotiations on the detail of unification could only take place after the referendums, citizens would not have a clear idea of what they were voting for. Moreover, the UK and Irish Governments would lack a clear mandate as to the form of unification they should be negotiating.

If negotiations between the Governments broke down, an Act of the Oireachtas—legally required by the GFA—would make Northern Ireland part of Ireland as a matter of Irish law. But Northern Ireland would remain part of the United Kingdom as a matter of UK law unless or until the UK Parliament passed legislation ceding sovereignty to Ireland. It is imperative that this risk be reduced. It would be a travesty to return to a situation where Ireland and the UK disagree on the constitutional status of Northern Ireland.

The best way to reduce this risk is to settle as much detail as possible about the form of unification prior to the concurrent referendums. People in southern Ireland would vote on the principle of unification and related constitutional changes that would take effect if there were a ‘yes’ vote in Northern Ireland. People in Northern Ireland would vote on the principle of unification, equipped with knowledge of the proposed constitutional structure of the new state.

For the details of a united Ireland to be settled before the votes, three to five years should elapse between the calling of the votes and the votes themselves. This would allow for formal negotiations between the UK and Irish Governments, interaction with the devolved institutions in Northern Ireland, and the engagement of ordinary people—north and south—through citizens assemblies and other means.

Notwithstanding all this negotiation, interaction, and consultation, the referendums would essentially involve the Irish Government making a nationalist offer both to people in Northern Ireland and to its own citizens. Northern unionists would—quite legitimately—have no incentive to participate in any form of discussions or negotiations unless or until unification was approved and irreversible. The Irish Government would have strong reason to make the offer attractive to unionists, both to solicit votes and to reduce feelings of alienation in a newly unified state. But it is difficult to see any formal engagement with political unionism prior to unification.

For this reason, I previously suggested a model whereby transitional arrangements could apply for several years post-unification, while the citizens of the new state collaborated on a new constitution. There is force, however, to the criticism that a legal requirement to this effect would reintroduce undesirable uncertainty at the time of the referendums over the form of unification. I still believe that a newly unified state should consider a new constitution to which all its citizens could contribute, but this should not be legally required as part of the unification process.

Oran Doyle is a professor in law at Trinity College Dublin and a visiting faculty member at the University of Pennsylvania Carey Law School. This post draws on a forthcoming working paper, co-authored with David Kenny, to be published by the Working Group on Unification Referendums on the Island of Ireland, convened by the Constitution Unit of University College London and supported by generous funding from the British Academy.

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