Long before Boris Johnson achieved his blond ambition to become Britain’s new prime minister, the comparisons with President Donald Trump were coming fast and furious. Aside from the extravagant hairdos, the penchant for monochrome ties, the serial philandering and the loose morals, both men have an uncanny propensity to dispense with facts that are inconvenient and to manufacture “alternative” ones as needed.

Neither has ever held an opinion that couldn’t be repurposed as the politics of the day might demand, and neither appear to have strong convictions about anything (other than perhaps their God-given right to ascend to their respective proverbial thrones). For example, Trump was for the Iraq war before he was against it. Not to be outdone by his U.S. counterpart, Johnson was in favor of Britain’s exit from the European Union — known as Brexit — even as he simultaneously opposed it. (A few months before the June 2016 Brexit vote, Johnson wrote an unpublished column for The Daily Telegraph in favor of Britain remaining in the E.U. while simultaneously publishing a column in favor of leaving.)

There is, though, one alarming difference between the two men’s ascent to power. Donald Trump was elected at a time of relative stability and economic prosperity in the U.S., while the ruling Conservative Party in Britain has appointed a Donald Trump-lite to the premiership while their country is facing its worst crisis since World War II — the quandary known as Brexit.

It is somewhat fitting, I suppose, that the man who led the campaign for Britain to leave the European Union, even while still “sorting out his own thoughts” on whether it was such a good idea, should now be the one having to sort through the ensuing catastrophe.

Three years after the 2016 Brexit referendum, with the Oct. 31 deadline for Britain’s departure fast approaching, the prospect of a hard Brexit — that is, Britain leaving the union with no deal in place to govern relations between the two entities on everything from customs and border control to cellphone roaming charges and driver’s license reciprocity — is becoming increasingly likely. Despite dire warnings from analysts about what a no-deal scenario would mean for Britain — long lines at border crossings and custom controls, broken supply chains and general economic chaos, not to mention an uncertain fate for Britons working in the E.U. and E.U. nationals working in Britain — Johnson remains unfazed and is still touting no deal as a preferred option.

And then there is the Irish question.

When Britain voted in 2016 to leave the E.U., it did so against the wishes of the majority in Northern Ireland who voted to remain and in spite of the aghast objections of the neighboring government of the Republic of Ireland. Part of the reason for their broad opposition was that, 21 years ago, the British and Irish governments entered a hard-won peace agreement, known as the Good Friday accords, which brought an uneasy end to 30 years of war in Northern Ireland (the so-called Troubles). A central component of the accords was the removal of the border between the Republic of Ireland and the six counties in the north, which remain under British control.

This was possible as long as Britain and the Republic of Ireland were both E.U. members — meaning that goods and people could move freely between Ireland and Northern Ireland and no border checks were necessary. Britain’s decision to check out of the E.U., which will eliminate border controls among bloc members, means that it, by default, checks out of the Good Friday accords as well, changing the status of the border between Northern Ireland and Ireland. Unless a deal is reached to avoid it, a hard border, and all the trouble that came with it in the past, will have to be reinstated when Brexit goes into effect.

Fortunately for all of Ireland, the E.U. is not prepared to enable Britain to undermine the accords even after it leaves the union and so is insisting on a “backstop” solution to the border question. That would involve Northern Ireland, and only Northern Ireland, staying in the European customs union if the U.K. leaves the EU without securing a deal. Outgoing Prime Minister Theresa May — who, for all her faults did, at least, operate within the realms of rationality — did her best to avoid leaving without a deal that could overturn a peace agreement that ended 30 years of violence. But despite spending the best part of three years negotiating with the E.U., she could not get her deal ratified by her own Conservative-led Parliament, largely due to objections to the backstop from members like Johnson.

The “hard Brexiteers” — who make up a significant portion of the Conservative Party but mostly seem to be scared of losing their districts to far-right politicians from an ever-shifting number of pro-Brexit parties that eventually are revealed to be rabidly Islamophobic — want a clean break from the E.U. and so won’t entertain the backstop solution, even as a temporary measure. Hard-core unionists in Northern Ireland, on whom the Conservative Party relies to secure its majority in Parliament, are also opposed to a compromise that saves the accords as they believe the backstop would alter their status within the United Kingdom.

True to Trumpian form, Johnson was for the backstop before it became more expedient to oppose it. He was part of May’s Cabinet and helped negotiate the agreement that included the backstop provisions, before resigning his post in 2018 and then denouncing the deal he had helped broker on the grounds that it would make the E.U. Britain’s “colonial masters.”

So here we are, just three months shy of the extended Brexit deadline, and all attempts to square that circular dilemma have failed. What does Johnson propose now that he’s prime minister? Not much other than cute slogans such as “Bin the backstop” and nonsense proposals to adopt a “can-do spirit” to find technological solutions to the border issue that do not currently exist.

Never mind that Britain is facing a near-term future of food and medicine shortages, never mind that Northern Ireland is on the verge of a resumption of mass violence — small incidents of which, including the killing of a journalist, have already occurred — never mind that U.K. businesses are moving overseas and shedding much-needed jobs at home.

There is one silver lining to Johnson’s fantasy cloud: His Conservative Party members are not as inclined to indulge his worst instincts as their Republican counterparts in the U.S. are to indulge Donald Trump. Several members of his own party voted with the opposition last week to block any possible efforts to circumvent Parliament in the pursuit of a no-deal Brexit.

Whether this will be enough to save Johnson from himself — or more important, to save Britain (and Ireland) from Johnson — is anybody’s guess.

CORRECTION: July 30, 2019 10:45 a.m. ET: A previous version of this article misstated the U.K.’s participation in the Schengen Agreement eliminating border controls in the E.U. It has not been part of the agreement, so Brexit will not change anything in relation to Schengen. (Ireland is also not part of the agreement.)