You can tell there’s a general election coming, because that’s the subtext to everything else that happens. Boris Johnson uses the G7 summit to grandstand to the domestic tabloids. Meanwhile the fractious coalition of anti-no-deal forces meets today to try and form a coherent plan to stop Britain crashing out of the EU – and to force an election.

If the object was to fight no deal through parliamentary process, the only people you would need in the room would be Dominic Grieve and Keir Starmer, with maybe somebody taking notes for John Bercow. But today’s get-together, convened last week by Jeremy Corbyn, is as much about a general election, which few people now doubt will happen sooner rather than later. Given that, it would have been better to enter the room in the spirit of anticipated unity, rather than publicly set out your red lines beforehand, as Jo Swinson has done. She reportedly wrote a letter to Corbyn yesterday, arguing that his insistence on leading a temporary government of national unity would be likely to scupper a vote of no confidence in the government.

One of the many things I look forward to, at the end of this whole ignominious business, is the prospect of politicians finally ceasing to flaunt their inflexibility as if it were a virtue. Because it isn’t.

Yet if Corbyn, Swinson and co can recognise a few elemental truths about their predicament, the meeting today could yet deliver something invaluable to those of us outside it: hope.

All remain parties and actors need to stop performing their oppositional moves and accept as an inevitability that they have to work together. Labour historically, and Jeremy Corbyn personally, have shown no aptitude or enthusiasm for progressive alliances, but the leader of the opposition must recognise that activists and members are going to work together regardless, as they did in 2017 (and as they did in 1997). There is a very plain advantage to be had for both Labour and the Liberal Democrats from reaching an understanding (the Greens stand to gain the least, I would guess; Caroline Lucas, fortunately, doesn’t fight for her own or her party’s collective ego).

According to yet-to-be-published projections made by Best for Britain, of the 150 marginals across England and Wales where a remain alliance could make the difference, in 111 the numbers dictate that the Lib Dems swing behind Labour. The benefit to Labour is obvious. For Swinson, 40-odd seats would still represent a massive uptick in her party’s fortunes.

Remainers on the centre-right, who are currently cleaving to what’s been called the Meatloaf stance (“I’d do anything for Europe, but I won’t make Jeremy Corbyn prime minister”) have to think more deeply about their objections. Whatever threat Corbyn may pose to capitalism, it is as nothing compared to the threat from vulture capitalists and high priests of disruption and chaos emptying their pots of cash into Dominic Cummings’ cauldron.

If the danger represented by this government bore any relation to its competence, we’d have nothing to worry about. But the disunity of the forces opposing it is giving it a potency it does not deserve. We will only haul ourselves out of this nightmare period when the politics of solidarity and co-operation wrests the controls from the politics of delinquency and destruction. That has to start in this meeting. There’s a good argument for them all to smoke a joint before they go in.

It is also increasingly clear that Labour has an additional challenge of its own: the party needs to pivot to “revoke”. Not as a peace offering to the other parties, but because it’s the only position that now makes sense. The idea of a Labour-negotiated deal, which protects workers’ rights, drives forward international cooperation on the environment, and maintains the EU as our major trading bloc, while differing meaningfully from membership of the EU, is fanciful. A second referendum, meanwhile, is pointless given that any general election will, itself, function as one: the Brexit parties are there for Brexiteers to vote for. Of course, if a government of national unity itself chose to revoke article 50, then arguably that would create a democratic deficit. But if, in the context of an election, the country is asked point blank whether it wants to leave or revoke, no such crime against the will of the people has been perpetrated.

The Conservatives and the Brexit party are making the vast unsubstantiated promise that a combination of grit, optimism and tech will solve every problem associated with Brexit. Some of us spend our time wondering why these arguments hold fast against any evidence to their contrary; why they’re so immune to reality and reason. But Labour now needs to make a vast promise of its own: revoke. In that moment, Brexit will be revealed for what it is – a civil war embroiling all of us that should have stayed within the confines of the Conservative party, where it belonged.

Boris Johnson and Cummings will not be waiting with bated breath to see if a vote of no confidence prevails. They will have their decision tree, with a general election on one branch, a no-deal Brexit on the other; it all leads ultimately to the polling booth, and all who oppose them should be ready for an election on the first possible date: 17 October, six weeks after parliament reassembles. And readiness is not a reheating of Facebook ads and leaflets with slightly-too-complicated promises; it is a united promise to revoke, from allies who put their nation ahead of their tired hostilities.

• Zoe Williams is a Guardian columnist