A familiarity with multiple titles and names is often a requirement in navigating, both metaphorically and literally, the complexities of politics and society in Northern Ireland. It is unsurprising, then, that the treaty celebrating the twentieth anniversary of its signing this week, and which enshrined the right of citizens in Northern Ireland to identify as Irish, British or both, is known variously as the Belfast Agreement, the Good Friday Agreement or, simply, the Agreement.

Without an Assembly or Executive, however, this momentous anniversary is being celebrated in a political void. Yet the achievements of the Agreement are anything but underwhelming. It confronted the legacy of decades of violence and division to provide the mechanism through which the two competing nationalisms in Northern Ireland agreed upon how they would disagree: through democratic consent and the accommodation of difference.

While Brexit has paralysed Northern politics, it only adds urgency to the need for a restored Assembly and to the need to ensure the Agreement is fully realised. Despite declarations to the contrary, the Agreement has not failed. It has been failed by those who prevented it being fully implemented, and the differential treatment it demands for Northern Ireland is the key to a workable Brexit solution for citizens from both political traditions.

The EU was a critical inspiration for the man who, more than anyone else, envisaged and designed the Agreement, John Hume. His interweaving of the EU throughout the three strands was deliberate, not least in the explicit reference to the two governments’ partnership in their common EU membership.

Brexiteers have shifted from dismissing warnings about damage Brexit would inflict on the Agreement to questioning its relevance altogether. It is by far the most inconvenient and immovable bulwark to a hard Brexit. But for all the headlines and rightful condemnation of such comments, they were nothing new. Many of those expressing the sentiments never supported the Agreement in the first place or were taking their lead from those who never did.

Opposition and platitudes from the usual suspects on the right should not obscure the fact that Northern Ireland has a unique constitutional settlement within the United Kingdom. So too does Brexit demand a unique solution. The ‘backstop’ option in December’s draft legal text triggered much furore about the constitutional integrity of the UK, yet not about the incorporating constitutional integrity of the Agreement.

Too many observers and commentators of the DUP have all too readily accepted that the party will accept no divergence from Britain. In fact, the DUP has previously demonstrated ample flexibility and innovation on divergence from Britain. Of course, its divergence from the British model of caps on the Renewable Heat Incentive payments was its most memorable and ill-advised case of doing so and significantly contributed to the collapse of the Assembly.

Yet the DUP has also recognised necessary competitive benefits of fiscal divergence from the UK – and harmonisation with the Republic of Ireland – in advocating for a reduced rate of Corporation Tax, lowering of Tourism VAT and the scrapping of Air Passenger Duty. There is no reason not to embrace such pragmatism again.

Doing so would benefit nationalists, unionists and others, just as EU membership has.

Brussels was a backdrop onto which both communities could project their understanding of the three strands of relationships, most obviously through Strand Two, through which nationalists were partially compensated for the Irish state’s revocation of its territorial claim on the North through a closer working relationship with Dublin. Unionists could allay any fears of the implications of this relationship by viewing it as the formalisation of cooperation that would have taken place within the EU context, regardless.

And, despite the DUP’s enthusiasm for Brexit, both communities have benefited from the closer relationship in areas such as integrated healthcare and associated improved health outcomes, cross-border trade, the all-island energy market and through the opening of the border as part of the wider the peace process.

Amid the tumult, the Agreement, despite its delicate interwoven layers of constitutional relationships, is a living instrument that can, and must, be fully utilised to meet the challenges of Brexit. The Government’s intention not to transpose the EU Charter of Fundamental Rights raises pressing questions about possible differential human rights protections for Irish citizens, North and South, and highlights the need to fulfil the still outstanding human rights and equality safeguards that the Agreement provided for, most prominent of those a Bill of Rights.

Moreover, rather than allowing Brexit to threaten Strand Two – the most EU-informed part of the Agreement – it should be strengthened to deal with the challenges faced. It already provides a framework for North-South cooperation and policy implementation basis through the bodies and North-South Ministerial Council, which has a remit to consider EU matters.

So too with Stand Three: the moribund British-Irish Intergovernmental Conference could be revived as a forum for engagement between the British and Irish Governments, and for ministers in the devolved regions. Here, the Agreement will not only be defended against Brexit, but its potential fully realised.

Our devolved settlement does differentiate us from Britain. The Agreement, with its provisions for close cooperation and integration on a North-South basis, can mitigate the damages of Brexit, while still steadfastly upholding the principle of consent. Accommodating duality and difference was the very purpose of the Agreement in the first place.