Two of Boris Johnson’s most reckless chickens are coming home to roost. To get hard Brexit into law and topple his predecessor, Theresa May, he told Northern Ireland’s Democratic Unionist party that he would allow no border in the Irish Sea. He promptly allowed one, and signed a protocol to the Brexit deal to that effect. An enraged DUP is duly refusing to let the new Northern Irish executive take office until that border goes. Johnson is now threatening to unilaterally renege on the protocol, in turn enraging the EU by flagrantly breaching the withdrawal deal. Precisely this trap was built into hard Brexit from day one. Everyone knew it. It was classic Johnson. He lied his way out of each scrape, sacking or ennobling colleagues according to taste. The absence of a new executive in Belfast leaves open the prospect of direct rule from London. If Johnson fails to dismantle the EU-ordained border controls at Belfast docks, the DUP will stall power-sharing. If he gives in and allows the world’s goods to flow freely into the Irish republic, the EU has threatened to retaliate in an all-out trade war. The question is what new “constructive ambiguity” – a euphemism for fudge – Johnson can conceivably fashion to get him out of this mess. Amid all the shouting and screaming of Brexit, quiet voices were warning: don’t forget Northern Ireland. The Brexiters dismissed it as a historical trifle. Since the UK would have tariff-free trade with the EU, the Irish border would be “frictionless”. No problem. Of all the deceits of hard Brexit, none was more blatant than the word frictionless. Johnson in effect ceded authority over the 40% of Britain’s trade that is with the EU under the pretence that he was “taking back control”. But it takes two to trade. Hundred-page forms and hours-long queues at Dover have been the result, with similar friction at the Belfast border. The M&S chairman, Archie Norman, protested last week that a staggering 700 pages of forms is required to get two trucks across the Irish Sea from England, requiring eight hours of work by 20 staff. The reality is that any border is a border, offering any number of impediments to trade. The EU was furious at hard Brexit. What on earth made Johnson think it would make his life easy? The prime minister’s first decision must be to call the bluff of the DUP’s intransigent leader, Jeffrey Donaldson. Stony-faced unionists have been the bane of British prime ministers back to Lloyd George. In 1921, the territory was gerrymandered to deliver a perpetual unionist majority, and the resulting one-party rule has caused Britain little but trouble. At this month’s local elections, that historic act of gerrymandering failed. An exhausted electorate split the unionist vote three ways; Sinn Féin has emerged in pole position. It could one day lead Northern Ireland, with care, towards eventual reunion with the south. Donaldson faces an existential threat and has nothing to lose. The Good Friday agreement of 1998 achieved peace by embedding power-sharing between the nationalist and unionist constituencies. With each side having a veto, it has constantly broken down and cannot survive formally without the leading unionist bloc, the DUP, in play. At the same time, Northern Ireland’s government is reportedly a shambles. In particular, its health service is delivering some of the worst outcomes of any part of the UK: just last week it was reported that the number of people waiting for more than 12 hours in A&E had doubled in a year. Somehow the logjam must be cleared. Johnson has to demand that Donaldson return to Stormont or that Northern Ireland must be ruled without him. Until power-sharing returns, with first minister designate Michelle O’Neill in post, London must find a mechanism for re-establishing the executive, with a role for O’Neill. This might involve some sort of “ghost” executive under the formal aegis of the Northern Ireland secretary. The reality is that democracy in Northern Ireland is starting to change, and in a welcome and more open direction. London has ruled its Irish territory abominably for over a century. It owes it help towards a new dawn. The short-term question remains whether Johnson can say anything to the unionists sufficient to entice them back. For most in Northern Ireland, the border is not the chief political issue. It has been replaced by the cost of living and the state of the health service. By the same token, it is clearly worth attempting yet again to plead with Brussels’ better nature to find some partial compromise on the border question. The present controls are indefensible. Hard Brexit was a mistake, a crude and casual gesture by Johnson to prop up his leadership bid. He showed no sign of knowing what “hard” might entail. But then there were few remainers ready to support “soft” Brexit as a halfway house. As it is, Brussels negotiators have clearly been instructed to play tough, subjecting British trade to a nightmare of barriers and bureaucracy. These are palpably beyond anything needed to protect standards, health and safety. At the same time, there is no reason for Britain not to accede to standards that it has shared with the rest of the continent for half a century. The proposals reputedly offered by the foreign secretary, Liz Truss, to ease the Belfast border are reasonable but inoperable, in the absence of the EU’s agreement. They embrace licensed “trusted traders”, and red and green lanes for vehicles intended to go on to Ireland and those remaining in Northern Ireland. A modicum of supervision should be able to protect the EU from global trade contamination. There is no need to chase trawlers across the high seas or follow British number plates through the lanes of Louth and Donegal. Surely there is compromise somewhere here. Europe has enough on its hands without the distraction of a childish trade war with Britain. Yes, Britain is to blame. It chose to leave the EU, but the EU should respect that. In addition, Johnson personally interpreted Brexit as leaving Europe’s economic trade area, for which he had no mandate. That decision is costing Britain dear and one day will, I am sure, have to be corrected. For the moment Johnson owes it to Northern Ireland to free it from the mess into which hard Brexit has condemned it. In doing so he could yet set it on the road to political reconstruction. That at least would be a silver lining on the Brexit cloud. Simon Jenkins is a Guardian columnist