Garvan Walshe is a former National and International Security Policy Adviser to the Conservative Party. He runs TRD Policy

Until this week I had thought that Brexit had become inevitable. The referendum victory, though narrow, was clear, and those who continued to oppose Brexit lacked the tactical sophistication to press their case successfully.

That’s started to change. The campaign to take Britain out of the EU is now at risk of failing altogether. But the manner of its failure, the scorched earth tactics of its more extreme partisans, and the increasing radicalisation of the Remain electorate (reflected in the Liberal Democrats’ tactically astute shift in position to direct revocation of Article 50, without a referendum) could cause a significant portion of the public to feel completely alienated from the political system.

So although I opposed Brexit, I still don’t think it should currently be reversed. Around half of Remainers still see EU membership in transactional terms: but David Cameron tested this idea of it to destruction. Many of the rest have turned into pro-European partisans, but out of opposition to Brexit, rather than love of European integration.

Should a stable majority of the British public come to understand that the European Union is a project of political integration that involves the nation states of Europe sharing sovereignty, then the UK should rejoin. But cancelling Brexit now would be bad for both the UK, which would find itself kicking against the loveless marriage to which it had returned, and the EU, which would have an unhappy and divided Britain to contend with.

The Brexiteers have failed internationally because they overestimated Britain’s power. And they failed domestically because they mistook a moral argument for a political one.

Their claim is that winning the referendum has created an unanswerable case for having some kind, indeed any kind, of Brexit. Both sides of the referendum campaign said that they would abide by the result, and that moral duty, they believe, is sufficiently strong that it should override other considerations, including Britain’s traditions as a representative, not a direct, democracy.

But moral claims on their own do not a political strategy make. Brexiteers needed to convert their victory into a broad and lasting consensus in favour of Brexit. It had appeared that May had planned to do just that when she became the Conservative leader in 2016, but she changed tack during her Tory conference speech that year in pursuit of a very specific hard-right fever dream that came unstuck the following July.

Its effects were to deprive May of a majority, force her to rely on the DUP, whose demands proved incompatible with those of the EU, as well as the need to avoid giving the SNP an argument to demand the same status as Northern Ireland, and resulted in the Withdrawal Agreement, which couldn’t pass the Commons, disastrous EU election results, the rise of the Brexit Party and her resignation and replacement by Boris Johnson.

Johnson inherited a war on two fronts — against the Brexit Party and the LibDems — and devised a sort of Schlieffen Plan to get the Conservative Party through. Complete Brexit by October, then pivot to the kind of One Nation Toryism he professed as mayor, to give a country tired of Brexit and austerity something to unite around.

Over the summer, it looked like he had maintained just enough ambiguity about his intentions to keep his opponents divided. Instead he united them by proroguing Parliament and horrified the party by taking the whip from 21 rebels, sparking the resignation of Amber Rudd, his own brother Jo, and even the Duke of Wellington. Whatever the Conservative Party is these days, it doesn’t have space for the descendants of Britain’s national heroes. Much of this is attributed to his senior adviser Dominic Cummings, who combines the flexibility of the younger Moltke with the defence-minded attitude of Marshal Foch.

Unable to force his policy through a parliament in which he doesn’t have a majority, having reduced that majority further by his purge, he has been outmaneouvred by Jeremy Corbyn; his bid to call an election twice blocked by the Commons.

Situation excellente says Cummings, j’attaque.

The quite obvious plan, as is clear from adverts promising a “People versus the Politicians” election, is to reactivate enough anger from Leave voters to win a parliamentary majority against a divided opposition. It’s a plan with superficial possibility. Some pollsters, particularly YouGov, are showing a sizeable Conservative lead. Others give a much closer result.

The fever dream to which I refer is that the Conservative Party will somehow extend its reach into the northern working class while still holding on to its urban professional vote in the cities and suburbs. Stirring up anger at the establishment and fear of Corbyn worked during the referendum, where Labour essentially gave up campaigning, but failed in the general election when it was able to hold onto their core vote. It would be quite a gamble, albeit in keeping with World War I inspired strategy, to repeat the 2017 plan two years later.

As I write, the Scottish courts have ruled Johnson’s prorogation of Parliament unlawful, prompting Number Ten to issue an attack on “Scottish” judges, questioning their independence. This latest Fochian outburst is highly unwise and should not have come from a government of a party that still calls itself the Conservative and Unionist Party.

The Supreme Court, which hears the appeal next week, has three options. It can declare prorogation lawful in both, allowing the SNP to say “English” judges overruled their traditions. It could declare it unlawful in both, which would, insofar as it upheld the Scottish verdict, require the Supreme Court to rule in effect that the Prime Minister had misled the Queen; or, it could produce the even more uncomfortable verdict that prorogation might have been lawful in England and Wales but unlawful in Scotland.

Also yesterday, a poll of Northern Ireland was released by Lord Ashcroft showing majority support there for the backstop, and an essentially evenly split vote on reunification with the Republic (51–49 in favour). The even split is maintained thanks to a majority of older voters continuing to support the Union. The youngest age group of voters breaks 60–40 in favour of a United Ireland.

The Johnson Government’s strategy of heightening the contradictions has so far been an unqualified failure. Prorogation united the opposition to require him to seek an extension if he stays in office. The attempts to call an election failed. The removal of the whip from 21 Tory MPs reinforced their determination to defy Number Ten. Polling for the election itself increasingly suggests it would produce another hung parliament

The Prime Minister needs to accept this failure and change tack. Leaving without a deal is no longer possible. Parliament will it. Substantive modifications to the deal are also out of the question. The deal itself allows for a wide variety of Brexits, from Canadian-style free trade to a Norway-style membership of the Single Market. It would allow the Prime Minister to pivot to the One Nation Conservatism needed to win centrist voters back from the LibDems, and of course, it would allow him to tell Brexit Party supporters that we had left the EU.

The Spartans who consider this capitulation should think very carefully. Theresa May said there were three options: this deal, no deal, or no Brexit. The effect of prorogation has been to take away the option of no deal by constitutional means. The choice left is now this deal, no Brexit, or no United Kingdom.