No version of Brexit avoids disruption for Northern Ireland and the peace process. Furthermore, it is inherent in the logic of UK departure from the European Union that, far from seeking to minimise this impact, it should augment the risks to the region. The concept of sovereignty – however defined – was always a key feature of Euroscepticism, and in 2016 the ‘leave’ campaign presented its cause in terms of a reassertion of this quality on the part of the UK. The UK government has now seemingly chosen this term as the keyword of the latest instalment in the Brexit process. In keeping with its fundamentalist approach to political messaging, it deploys the term in efforts to trump the realities of negotiation from a position of disadvantage in which the UK has placed itself. When spokespeople for the UK government refer to sovereignty, they have in mind a particular version of it: that a country either possesses it absolutely, or does not at all, and that it cannot be shared or qualified. Moreover, they treat the absolute necessity of maintaining sovereignty so defined as axiomatic. It is, as they present it, both the objective of the process from the UK standpoint, and the reason that the EU must bow to UK demands.

Such an outlook could not be reconciled with membership of the EU – as was the intention of those who asserted it. But it is also difficult to combine with an exit from this organisation on anything other than the most damaging terms, economically, politically, and even from the point of view of security. The UK, moreover, is party to international agreements that (while, as discussed below, not always precise in their implications) seem not to be congruent with the version of sovereignty which the Johnson government is determined to advance. One such agreement is the Belfast/Good Friday Agreement of 1998; another is the Withdrawal Agreement (and the Northern Ireland Protocol within it) into which the present Prime Minister entered in 2019. Its response to this tension has been unilaterally to reinterpret those texts in ways that fit better with its disposition, and (as I have discussed in a previous paper) to weaponise those new definitions within the negotiating process.

It has done so lately with regard to the 2019 Withdrawal Agreement, as demonstrated by the UK government paper published on the subject last month. The basic approach of the UK government is to seek to present the 2019 Agreement as a basis for further negotiation, when it was in fact the outcome of prolonged negotiation intended for implementation. As part of this general approach, the paper attempts to minimise the significance of the Northern Ireland Protocol by presenting it as a fleeting phenomenon, stating that: ‘The Protocol is not codified as a permanent solution…The implementation of the Protocol must therefore reflect the reality that the alignment provisions may not be in place for ever.’ While it is true that – after a minimum of six years – Northern Ireland can withdraw from some but not all of the Protocol, no arrangement will necessarily hold forever and this fact does not excuse countries from fulfilling their obligations. Alongside downplaying the significance of the agreement into which the UK entered in 2019, the paper also seeks to distort and revise its meaning. For instance, in its discussion of the handling of goods moving between Great Britain and Northern Ireland, it states that: ‘There should be no tariffs on internal UK trade…Tariffs should only be charged if goods are destined for Ireland or the EU Single Market more broadly, or if there is a genuine and substantial risk of them ending up there.

As Katy Hayward of Queen’s University Belfast has noted, the words ‘genuine and substantial’ are not in the original text of the agreement, which only refers to a ‘risk’ of goods finding their way into the Single Market. Here we see an example of the impact of the overriding imperative of upholding a certain version of sovereignty. It has led the government to seek to soften the meaning of an agreement in an effort to reduce its responsibility for implementing an agreement it has reached.

But among the confusion and posturing, the paper also appears to have accepted certain propositions that arise unavoidably from the exit deal, but over which it recently appeared to be vacillating. It accepts that the protocol will apply with or without the reaching of a wider Free Trade Agreement between the EU and UK. The paper acknowledges – albeit grudgingly and with problematic qualifications – that it will need to operate some kind of internal tariff barrier within the UK between Great Britain and Northern Ireland; that it will involve checks and charges for which the UK is responsible; that the EU will need to have some kind of observation role; and that ‘the Protocol gives effect to certain aspects of EU law in Northern Ireland’. These concessions to the reality of the Withdrawal Agreement amount to a tacit acknowledgement of the impossibility of realising the binary version of sovereignty to which the UK government is rhetorically wedded. The position is inherently unstable. It is therefore worth discussing a range of possible post-Brexit constitutional options for Northern Ireland. In doing so, I draw and elaborate upon five options set out in a previous paper (though I have reordered them).

The first option – and the basis on which the UK left the EU in January 2020 – is that of introducing a barrier within the UK, operating between Northern Ireland and Great Britain. The purpose is to allow Northern Ireland, while continuing as part of the UK, to preserve alignment in key areas with the EU, avoiding a hard border, while also protecting the integrity of the European Single Market. Early in the post-referendum Brexit negotiations, the EU seemingly preferred an option of this type. But the Theresa May administration judged it to be politically unacceptable, because of the division it would introduce within the UK. Upon becoming premier, Johnson reverted to this proposal, though presumably not on the basis of an assessment of its practical viability. The complications that have subsequently arisen in reconciling the UK stance regarding sovereignty with this arrangement help to illustrate the misgivings that May and her government (within which Johnson was Foreign Secretary for two years) had. For instance, the present UK government proposals seem to envisage Northern Ireland effectively being jointly subject to two different customs systems, yet with minimal bureaucracy and light-touch enforcement mechanisms, surely a difficult outcome to realise.

The more the UK diverges from EU regulations and tariff levels, the greater such tensions will become. But the very purpose of the Northern Ireland aspects of the Withdrawal Agreement is to allow for such differentiation, while recognising the special status of Northern Ireland. Indeed, it appears to be a policy of the UK government to reduce the difference between a Free Trade Agreement of the type it aspires towards and a ‘hard’ Brexit, which the self-imposed UK deadline makes more likely. It seems likely therefore that difficulties will intensify over time. If the UK sought to maximise continuity with the EU post-Brexit, then the protocol might be more workable. But to do so would be to contradict the logic of Brexit. It is possible that some future political convulsion will produce a government with a policy of closer alignment with the EU – perhaps preparatory to, or as a substitute for, renewed EU membership. But this turn of events is not in immediate prospect. Therefore, whether the EU and UK reach a wider Free Trade Agreement, or if a ‘hard’ Brexit occurs (assuming no extension is activated), sustaining arrangements for Northern Ireland will prove challenging.

If for some reason the arrangements set out in option one fail, either in the short term or at some point in future, option two could come into play. It involves the appearance of a hard border on the island of Ireland. The most likely trigger for such an outcome would be failure by the UK to fulfil its requirements to prevent the use of Northern Ireland as a surreptitious transition zone from Great Britain into the Single Market. If the UK is able – in line with its intentions – to secure preferential agreements with third parties that involve lower tariffs on goods from those economies, the risk of such an outcome will increase. The EU may feel forced to impose border controls. We should not entirely discount that movement in goods in the opposite direction could also present difficulties, and that it could create problems from the point of view of either the EU or the UK, or both, that could in turn generate pressure to compromise freedom of movement of goods and people between the North and the Republic. This outcome would be disastrous from the point of view of the peace process and the general stability and prosperity of the region. It is doubtful that it would ultimately be acceptable to any of the players involved and that a new arrangement would be needed. But, other than a return to option 1, which would presumably have been found wanting, what would be on offer?

Option 3 could be that the EU (and/or the UK) chose to tolerate the violation of their customs unions or areas, and perhaps the regulatory integrity of their internal markets. This option, presenting as it would various practical and political problems, would surely be unstable, and would undermine the credibility of the EU and the UK, to the detriment of both. Not only would it create internal economic difficulties for them, it would make them appear less attractive trading partners, since their leakage could contaminate those who they had reached special arrangements with. To become a centre for rule-breaking and contraband is surely not a desirable goal for Northern Ireland or those with an interest in it.

In option 4, the Republic of Ireland, faced with the imposition of a hard border between it and Northern Ireland, would choose unity for the island of Ireland by aligning itself with the UK rather than the EU for customs and regulatory purposes. Even suggesting that it do so, given the historical sensitivities involved, is an incendiary act. Were such an arrangement to come into force, it would create a perception of improper coercion by the UK. The various forms of damage for the island of Ireland, including for the process, would surely be immense. Furthermore, the international reputation of the UK, as a country with a legacy of imperial impulse that is unwilling to fulfil obligations accrued from its own past, would suffer considerably.

A fifth option would involve uniting Ireland by other means: the North joining with the Republic in an arrangement that allowed both to retain full participation in the EU, presumably outside the UK. An argument in favour of this arrangement is that it is allowed for by the Belfast/Good Friday Agreement. It has always been a long term possibility; and if the remainder of the UK (with or without Scotland) is set upon Brexit, then it must accept that a price of achieving this goal (for those who regard it as a desirable outcome) might be the unpicking of the Union. A benefit of this approach – however it was realised precisely – could be that it would facilitate a focus on a bilateral, North-South relationship, ending the trilateral dynamic within which London has lately come to play an irrational and destabilising role. Any such arrangement would necessitate an effort, as far as possible, to reassure the unionist community within Northern Ireland, and it might be that the utilisation of trusted traditional symbols and institutions, such as the monarchy, could be of value. When assessing and refining this option, certain questions must be addressed:

How, precisely, would it be arrived at, over what period of time and with what intermediary confidence-building steps? While the peace process and other agreements imply a more sophisticated approach to sovereignty than the binary model, they are not entirely clear about what the alternative form is, or how it can be realised. Departure of Northern Ireland from the UK, for instance, requires consent in Northern Ireland via a referendum. But the power to call the referendum ultimately rests with the UK secretary of state. If the vote is held and favours leaving the UK, the UK government is obliged under the 1998 Agreement to introduce a bill to Parliament giving effect to this decision, but the final say rests with Parliament. While these obstacles are surmountable, they are indicative of the assertion of a new version of sovereignty within the framework of the old. A referendum campaign itself would present challenges, including the regulations applied and the part of official institutions within it.

Work on this subject is ongoing, but obvious further questions present themselves, including:

What part would the Republic play within this process, and what might be prevailing attitudes within it towards some kind of incorporation with Northern Ireland?

What constitutional system would characterise the incorporated island of Ireland? Might some kind of federal system be appropriate? Would consociationalism offer useful guiding principles?

What might be the relationship with the remaining UK, and with other components that are presently part of it, in particular Wales and Scotland?

It will be tempting for some actors to conclude that Brexit, especially a “no deal” Brexit, has brought a united Ireland closer in time. This may or may not be the case, but it has certainly not made the bringing about of a united Ireland a straightforward proposition, administratively or politically.