It isn’t every day that former prime ministers set old party enmities aside to deliver a unified message on a matter of national urgency. When John Major and Tony Blair did it in June 2016, warning that Brexit would jeopardise the delicate balance of peace in Northern Ireland, it rightly led the news. But not for long: the two prime ministers did not grace a single English newspaper front page the following morning. The media caravan moved on briskly. Besides, Northern Ireland was exactly the kind of serious, complicated and historically knotty subject that referendum coverage swerved to avoid. In fact, in a survey by King’s College London, analysing 350,000 articles in print and online across the 10-week referendum campaign, Northern Ireland didn’t register as an issue at all. One of the remain side’s biggest mistakes (one among many) was to campaign as if the result depended on the consequences implied by the question on the ballot paper; as if Britain would choose whether to reject EU membership on the basis of what that decision meant. The leave side fought instead on the basis that the decision could mean anything you wanted, and that so-called consequences were scare stories put about by a cosy elite with a vested interest in the status quo; people like Blair and Major. Six years later, the structure of the argument hasn’t changed. Only pro-Europeans speak of consequences, while Brexiteers campaign against them, as if the remainers won. Only, with Boris Johnson in Downing Street they can now write their delusions into law. That is the perverse genesis of the bill that was published on Monday, ostensibly to fix the Northern Ireland protocol of the withdrawal agreement – the treaty that Johnson signed in 2019. The proposed law would give ministers the power to erase and rewrite whichever parts of the old deal they don’t like. There is no need to study the small print to grasp how egregious an offence this is to norms of international diplomacy. Treaties exist to guarantee continuity and stability in relations between states, so that even capricious leaders can be relied upon to deal with neighbours and allies according to fixed parameters. A country that dispenses with that obligation is going rogue. It is revealing also that the bill targets every aspect of the protocol, not just the customs procedures that cause symbolic and constitutional distress to unionists by erecting barriers between Britain and Northern Ireland. If ministers were sincere in their claim to be focused on the border issue, they would not be roving off into the legislative weeds, pulling up anything that looks like European court jurisdiction or regulatory alignment. Pursuit of those targets is a sign that a policy nominally made for Northern Ireland has been customised to indulge the obsessions of English Tory Eurosceptics. The dictation was taken by the foreign secretary, Liz Truss, who recognises the influence that the hardline European Research Group of MPs will wield in any future decision about the Conservative leadership. For the same reason, Johnson cannot defy the ERG, although Downing Street has been briefing that its demands have not been swallowed whole. An even more extreme approach would have legislated for instant destruction of all bridges to Europe. The current version only creates a mechanism for burning them without notice. That capacity is contained in “delegated powers” – statutory instruments by which ministers can make law with barely any parliamentary scrutiny. MPs who vote for the bill would be signing away their say over any deal that Johnson thinks he might do to replace the one he is now sabotaging. That is an affront to democracy, but also a potential route back to diplomacy. It is the latter reason that makes English Brexit ultras and Northern Ireland unionists hesitant in endorsing a plan that only exists for their gratification. They surmise, correctly I think, that Johnson could yet flinch from the full-on confrontation with Brussels that his actions appear to be courting. He wants the spectacle of a domestic political battle – where his enemies can be cast as a remainer revanche – but not the economic pain that would follow a total breakdown in cross-Channel relations. He wants to lead a heroic charge against the mythic dragon “Europe”, stubbornly still breathing fire despite past slayings, and now holding the damsel “sovereignty” captive in Northern Ireland. Of course he does. It is the fable on which his career was built. In the last telling, in 2019, it ended with the coronation of King Boris. Meanwhile, in the real world, the prime minister has a chancellor who counsels against a trade war with the real Europe in the middle of a real cost-of-living crisis. In the real world, Northern Ireland is the only part of the UK outside London with a growing economy, thanks to the unique access it enjoys to the single market – a benefit of the protocol which has the support of parties representing the majority of voters in last month’s Stormont elections. Also in the real world, Brussels cannot meaningfully negotiate with a prime minister who reneges on treaties, and who has only fragile command of a party that doesn’t trust him either and where European policy is decided by MPs who will never be satisfied with any deal. They can’t be satisfied because the outcome they crave is release from a world where the single market matters, where the EU is a powerful economic entity and where Britain must compromise to restore privileges that it discarded, thinking they were burdens. That is the real meaning of the Northern Ireland protocol bill. It is not, as its defenders claim, a remedy for economic problems caused by customs checks on goods crossing from Great Britain. Nor will it succeed in palliating the offence caused to unionists by the existence of a regulatory border in the Irish Sea. It will not shock Brussels into concessions, or persuade anyone who thinks Johnson is a feckless prime minister that he is anything else. It is the inevitable degeneration into absurdity of government defined by Brexit. It is a doctrine that makes an enemy of reality. If that foe will not yield to rhetoric, it must be suppressed by law.