Last week, amid all the turmoil in the Tory party, there was a brief flurry of interest in the emergence as a candidate for prime minister of the man more than one British reporter referred to as “the Northern Ireland secretary Brandon Lewis”. Lewis was not the Northern Ireland secretary. He wasn’t even the previous holder of the office – he was the one before that. Likewise, when Rishi Sunak was eventually selected, at least one distinguished British commentator proclaimed him the first person of Asian heritage to become prime minister of a European country. Actually, the first such leader was Leo Varadkar, who became taoiseach in Dublin five years ago. These are minor slips, and all the easier to forgive when political events are following the vertiginous logic of a fever dream. But they do serve as a reminder that the so-called border down the Irish Sea is not just a trade barrier. There is also a haze of psychological detachment – keeping track of who’s in office in Dublin and Belfast is not, for most people in England, all that important. Thus, when the actual Northern Ireland secretary, Chris Heaton-Harris (the seventh since the Brexit referendum), announced on Friday that he is calling a new election for the devolved assembly, his decision scarcely registered above zero on the Richter scale at Westminster. Small earthquake in Belfast – not many dead. Who really cares that the election will fit precisely Ambrose Bierce’s definition of a road as the path “along which one may pass from where it is too tiresome to be to where it is futile to go”? The politics of Northern Ireland are tiresome enough without this exercise in electoral futility. No one expects the outcome to be significantly different to that of the assembly elections last May. No one believes that the Democratic Unionist party will have any incentive, in the tribal atmosphere of a new election, to soften its insistence that it will not allow the assembly to function or an executive to be formed until the Northern Ireland protocol of the Brexit withdrawal agreement is scrapped. Unless something else happens, they will all be back again in the same frigid halls of Stormont, bedecked perhaps with boughs of holly, but with no Christmas cheer to lighten the political gloom. Perhaps, then, there really is no reason why anyone on the eastern shores of the Irish Sea should be bothered by it all. Except that the very pointlessness of the election does make a bigger point. For what is going on in this theatre of the absurd is another episode of the Brexit show. The collapse of Northern Ireland’s political institutions, and the breakdown of the internal arrangements envisaged in the Good Friday agreement, are predictable consequences of the DUP’s crazy zeal for a hard Brexit. Northern Ireland has often been the place where the detritus of British politics – old sectarian attitudes, old colonial habits of mind – washes up and lingers. This is now happening again with Brexit. The great revolution of 2016 has become almost unspeakable in British politics. Boris Johnson’s boosterish babble is silenced; Keir Starmer has excised the B-word from his vocabulary. There is a deep desire not to talk about it. But Northern Ireland is where its political effects are unavoidable. At the heart of the political crisis in Northern Ireland is the DUP’s inability to take responsibility for the effects of its passionate embrace of the Brexit ultras in London. For the DUP gave birth to the protocol. Its horror is repugnance at the face of its own child. It is this weird reality that makes Northern Ireland currently ungovernable under the arrangements agreed in 1998. There were – and still are – only three ways to deal with the consequences of Northern Ireland being forced, against the will of its people, out of the EU. One is a hard border on the island of Ireland, which is unacceptable. The second is what Theresa May ended up with in the infamous “backstop” – all of the UK would in effect remain in the single market and the customs union, thus avoiding the emergence of different trading regimes on the two sides of the Irish Sea. The DUP got this outcome from May. The party rewarded her by helping to bring her down and put Boris Johnson in power. Because of this insanity, there was only one remaining possibility: a so-called border down the Irish Sea. The DUP hates it – and, from a unionist perspective, it is quite right to do so. But by helping to bring down May, it made it entirely inevitable. This, of course, it can never admit. It is left to rail against its own creation and to use the only power it now has, which is to paralyse politics in Northern Ireland. Instead of calling a patently purposeless election, the British government has to face its own responsibilities in all of this. By threatening to tear up the protocol, and hence resile from the withdrawal agreement, it has merely encouraged the DUP to believe that its historic error can be wished away. It is, in effect, suggesting that the unfortunate people of Northern Ireland can solve the mess of Brexit by voting in a useless election. They can’t. But Rishi Sunak can – if he faces down the Brexit ultras, recommits himself to obeying international law, and engages in proper negotiations with the EU to make the protocol work better. It is the first test of whether he can begin to make Britain a serious country again. Fintan O’Toole is a columnist with the Irish Times