With the spectre of a new hard Border haunting the island, the recently dormant question of Irish unity has received renewed attention. Unification was a major issue in the recent Fine Gael leadership contest, Fianna Fáil have promised a White Paper, and Sinn Féin have again called for a referendum. The DUP's support for Brexit and its customs and immigration restrictions – against public opinion in Northern Ireland – means we now require serious, long-term engagement with all parts of Northern society about the best shared future for the island. This must include thinking about how, if it were ultimately desired on both sides of the Border, a united Ireland could be constructed.
The Belfast Agreement envisages a united Ireland created through the passage of referendums on both sides of the Border. Beyond these mandates, there is no clarity about what would happen next. How would unification be executed? What would be the constitutional structure of a united Ireland? What negotiations and compromises might be necessary? We need look no further than the Brexit negotiations to see that popular will alone does not constitute a coherent plan.
The 1990 reunification of Germany would offer the most straightforward constitutional model. Rather than founding a new united Germany through article 146 of its basic law, West Germany instead used article 23 to absorb East Germany as additional provinces of the existing federal republic. Avoiding a lengthy process of constructing a new state and constitution – which would have opened up thorny issues for both sides – the parties quickly negotiated a treaty and reunification was completed in six months. This has generally been assumed to be the default route to a united Ireland. But how feasible would a German model be, and how would it work under our Constitution?
History casts long shadows in the northern sun. Even if public opinion was to move towards unity, joining the existing Republic would present significant political and cultural challenges to some parts of northern society that have deep-rooted suspicions that our state was not created to include them. There would be a Pandora’s box of symbolic issues, from flags (the Tricolour is defined by article 7) to language (Irish retains primacy under article 8), that could require negotiation and possibly a series or bundle of referendums. The Republic could become tied in the same Gordian knot of symbolic wrangling that has recently paralysed Northern politics, and the process of unification might become bogged down.
Religion has traditionally been the cause of much unionist suspicion towards the Republic, yet while our Constitution contains some highly religious language, it retains little legal effect. Our constitutional rights now have no connection to Catholicism or religion in their contemporary implementation by courts, and could suit a country of any religious composition.
Other issues of political identity might also pose challenges if compromise is required on institutions such as the head of state. Considering a retained role for the British monarch – as recently envisaged for an independent Scotland – would be a cultural and constitutional minefield. Rejoining the British commonwealth would probably be constitutionally possible, but would also prove controversial.
There would be questions of political representation too. The Constitution has no barriers to incorporating full Northern representation in the existing Oireachtas. Under article 16, constituencies and the size of the Dáil can be changed by law, though the current constitutional apportionment – at least one TD for every 30,000 people – would require more than 220 TDs for the whole island. A referendum allowing lower ratios or larger constituencies could be considered, but the question of representation would be fraught with controversy given the effects on the nation's political dynamics, and the difficulty of drawing 'fair' Northern constituencies.
Changes in the Upper House would be more straightforward: the Seanad's electoral system can be significantly changed by law, and representing Northern Ireland in a reformed Seanad with direct election would not be constitutionally difficult.
Perhaps the greatest question would be the autonomy of Northern Ireland. Article 15.5.2 contains a heretofore-unused provision that allows the Oireachtas to create or recognise "subordinate legislatures", so the Northern Assembly could be retained, although the enlarged Oireachtas would remain the supreme legislative body (especially regarding taxation and expenditure). The Constitution includes no detail on how such devolution would work and what its precise limits would be, so this would require substantial consideration.
Prior agreement across this whole range of issues would be essential to the success of a German model in Ireland, but if joining the Republic was not acceptable to the people of Northern Ireland, or if the necessary constitutional revisions prove too complex, a new constitutional settlement would have to be considered. This would permit a clean break with the past and give Northerners a sense of belonging in a new state, but starting from scratch would present other problems.
A new constitution would also mean that many aspects of our Republic – the status of the language, the Tricolour, a political history and culture built over a century of independence – would be up for discussion and subject to compromise.
Irish unity remains a distant dream, but with Northern Ireland increasingly failed by British and DUP government it is incumbent on us to offer our neighbours realistic long-term alternatives. The key to achieving Irish unity is persuading people of all backgrounds that a united Ireland offers a better future than neglect and isolation in a post-Brexit UK. We must be guided by the words of article 3.1 of the Constitution, that the unity of all Ireland’s people should include “all the diversity of their identities and traditions”.
With a willingness to undertake negotiation and revision, the Constitution might have the flexibility to incorporate Northern Ireland into the Republic, but we must consider both the need for dialogue and compromise, and the challenges and opportunities of all models of unification. Moving beyond our island’s deep-rooted partition will require open imagination.
Dr Christopher Kissane is a historian at the London School of Economics and Political Science. Dr David Kenny is Assistant professor of constitutional law at Trinity College Dublin