On Monday, Brexit negotiations over the Irish border broke down in spectacular confusion, leaving a number of unanswered questions amid the claims and counterclaims.

Did Theresa May actually agree on a text with the Republic of Ireland and the EU, before withdrawing her assent? Was it the DUP, the Conservatives’ ally in Northern Ireland, that scuppered the arrangement? And can the two sides now find a form of words that satisfies both the Irish government and Ulster unionists, so that talks move on to discuss a potential trade deal?

Irrespective of the final outcome, Brexit has caused an alarming breakdown in communications with our nearest neighbour.

Over the past few weeks, British commentators have castigated Dublin for misreading UK politics by demanding that Britain in its entirety, or Northern Ireland at least, stay effectively in the single market and customs union. Meanwhile, Irish pundits claim that ‘the Brits’ don’t understand or care about Ireland’s legitimate concerns.

In the UK, the Republic’s Prime Minister, Leo Varadkar, is accused of inexperience, plotting to achieve a united Ireland or using Brexit to campaign for domestic political support. His Fine Gael administration is still contemplating a possible general election early in the new year, after which it worries that Sinn Fein will hold the balance of power.

On the other side of the water, it’s alleged that Britain is cavalier about valid Irish concerns over a potential ‘hard border’ on the island, that could damage trade and endanger fragile relationships across the sectarian divide.

In spite of this unfriendly atmosphere, it’s possible to recognise that Dublin’s distress about Brexit is authentic, without accepting its overall analysis or acceding to its demands.

The Irish government has expressed misgivings about the border that are genuine and reflect concerns held widely by nationalists in Northern Ireland. Then again, it shows little understanding or respect for Ulster unionists’ equally sincere desires to be treated as full citizens of the UK.

Throughout the Brexit negotiations, Leo Varadkar and his ministers invoked the Good Friday Agreement, in an attempt to support their position. The ambiguous, leaked paragraph that emerged from Britain’s discussions with the EU on Monday even linked protecting the peace accord to “continued regulatory alignment” with the single market and customs union, north of the Irish border.

Yet, despite a tendency to mention the agreement as if it were a sacred text (while rarely citing specific clauses), nationalist Ireland has never quite accepted the consequences of its central tenet, the ‘principle of consent’. This principle determines that the people of Northern Ireland will decide whether their constitutional future lies in the United Kingdom, or a thirty-two county Irish republic.

It’s unlikely that Ireland’s government is actually implementing a dastardly master-plan to loosen the province’s ties with the rest of the UK and edge it toward a united Ireland. Dublin’s foreign minister and deputy PM, Simon Coveney, previously stated that he wants to see Irish unity within his ‘political lifetime’, but last week assured readers of the staunchly unionist News Letter that, “there is nothing (in Ireland’s Brexit negotiating position) which remotely threatens Northern Ireland’s constitutional status”.

Nonetheless, the Irish government behaves as if Britain’s authority over a part of its own territory were heavily qualified.

That’s partly because the Good Friday Agreement was so successful at defining a political dispute over sovereignty in terms of identity. Nationalists, and Sinn Fein in particular, persuaded their supporters that the agreement transferred control from London to the island of Ireland and secured an enhanced status for the Irish nationality in Northern Ireland.

Then, after Brexit, the hard edges of sovereignty began to re-emerge and demonstrate that Westminster’s power had not been curtailed meaningfully. The courts quickly rejected a number of attempts to argue that the UK cannot leave the EU, because of the Irish ‘peace process’.

Perhaps that’s why Brexit has caused so much angst among nationalists in Ulster and, alongside more practical concerns around the likely effects on the Republic’s economy, it helps explain why Dublin has found it so difficult to accept.

As a consequence, the idea has flourished that leaving the EU is a threat to peace in Northern Ireland or to the identity of Irish citizens there. Much less attention has been devoted to the entitlement of Northern Irish unionists to have their region regarded as an integral part of the UK.

The biggest unionist party, the DUP, supported leaving the European Union, while its main rival, the UUP, backed remain. Both parties now accept, without any ambiguity, the government’s right to implement Brexit in Northern Ireland.

The Irish government makes friendly overtures to unionists, but can’t quite grasp that their Britishness is grounded in a deeply felt allegiance to the United Kingdom and a desire to play a full role in its political, commercial and cultural life.

Although Dublin would be horrified if, at any time in the near future, it faced the disruption and expense of absorbing Northern Ireland into an all-Ireland republic, its attitudes are shaped by nationalist assumptions that the six counties aren’t quite a ‘real’ part of the UK.

This failure to understand the unionist position was exemplified when Varadkar chided the DUP, in response to the apparent collapse of Britain’s deal with the EU. The party, he pointed out, doesn’t represent most people in Northern Ireland and a minority of voters there voted against Brexit.

That may be true, but even unionists who voted ‘remain’ recognise that the referendum was held on a UK-wide basis and that its mandate cannot be picked apart. Northern Ireland voters weren’t asked whether they wanted to prioritise links with the rest of the island over links with the rest of Britain, much less whether they wanted to prioritise membership of the European single market over membership of the British internal market.

The UK and the EU may yet reach an agreement that contains enough ‘constructive ambiguity’ for talks to move on to trade. David Trimble liked to use that phrase, attributed originally to Henry Kissinger, to describe the Good Friday Agreement; which could serve either as an inspiration or a warning for unionists, who have seen the document bent and stretched to support all sorts of dubious demands.

Pro-Union parties in Northern Ireland should certainly strive to be flexible and pragmatic.

‘Alignment’ of regulations is not necessarily the same as membership of the single market and customs union, which means that the Irish aren’t getting their preferred option in every particular. The scope for the UK to drastically depart from Brussels’ rules is probably exaggerated in any case, as British firms will continue to export to the EU and some sectors of the economy, like agriculture and energy, are likely to remain closely linked across the British Isles.

At a minimum, unionists will surely resist any arrangements that could damage trade between the province and Great Britain. Northern Ireland sells four times more to the rest of the UK than to the Republic of Ireland and it would be economically disastrous if that business were reduced or if access to any future trade deals that London negotiates after Brexit were limited.

If an agreement on the first phase of negotiations damages the UK’s territorial integrity, anger from Northern Irish unionists, and many members of the Conservative Party, will be justified. They will also have a strong argument that the ‘principle of consent’ has been undermined and the terms of the Good Friday Agreement seriously compromised. Ireland’s government and Irish nationalists don’t have a monopoly on making claims on that notoriously slippery document.           

Owen Polley writes regularly for the Belfast Telegraph, the News Letter and the Irish News in Northern Ireland.  He co-authored of An Agenda for Northern Ireland after Brexit, for Global Britain and Sandelford Policy.