I’m old enough to remember when “Caroline Lucas should lead a national unity government” was just another fringe idea found in the hinterlands of Twitter. Alas, a week is such a long time in politics that Caroline Lucas has managed to jump on the bandwagon herself. As a Green party member I find the whole thing intensely embarrassing. Yes, the party has its share of weirdos and cranks, just like every other party, but they have been on the right side of the most important political divides in our country for longer than Labour, and that’s no small thing.

Before 2015, the Greens were your only realistic choice if you wanted a wholeheartedly anti-austerity, anti-workfare party. Now that the Arctic is regularly catching fire it makes even more sense to support a party with environmental policy at its core. Unfortunately Brexit seems to have proven just as brain-meltingly toxic for the Greens as it has for every other party. Lucas, usually a canny parliamentary operator who can punch well above her weight, has inexplicably tied the party to an unworkable fantasy that only exists because hard remainers dislike Jeremy Corbyn more than they fear a no-deal Brexit. And that’s without even getting into the fact that her fantasy 10-woman cabinet did not include a single woman of colour.

No national unity gubbins can get past the fact that all roads to stopping Brexit run through a Labour government

It makes sense that centrists, having seen their ideology’s reputation tank with the public, have now decided that democracy is a luxury we can no longer afford. It’s a mistake, though, to see Brexit as being caused by too much democracy. Instead it should be seen as the result of the UK’s democratic deficit. This cannot be fixed by telling people to sit down and be quiet: proper accountability, not technocratic backroom deals, is what’s needed if parliament is to regain its legitimacy after this mess.

Ironically the argument “we just want to stop no deal” comes after the hard-remain faction’s longstanding accusal of Corbyn as being a crypto-leaver because Labour’s policies reflected a compromise between the party’s soft-leave and remain wings: exactly the alliance this temporary government is supposed to be unifying against the hardline no-dealers. It’s impossible to say what might have happened if this broad anti-no deal arrangement had been sought in 2016, or if certain factions hadn’t been so keen to use remain as an anti-Corbyn Trojan horse. Even now, despite the fact that they’re trying to implement what basically amounts to Labour party policy, they are still throwing a tantrum over involving the Labour leader.

Corbyn’s personal beliefs on Brexit are presented as the obstacle to working with him, but this contradicts the omnipresence of Yvette Cooper in every Stop Brexit fantasy proposal. Cooper’s position on Brexit is barely distinguishable from Corbyn’s: if anything, she is more hardline on some issues, like freedom of movement. It is difficult not to conclude that, even at the 11th hour, the problem is not Corbyn’s beliefs but a resistance to him as prime minister, whatever the circumstances.

That’s why it makes no sense for Lucas to get involved in these shenanigans. There is much more alignment between Green party policy and the direction of Labour under Corbyn than there would be if the centrists succeeded in wresting back control of the party. The Greens don’t need to wholeheartedly back Corbyn, and should still campaign against Labour where the parties are in disagreement. But they should recognise that as a minor party it does them much more good to work with those who agree broadly with their overall policy platform than to seek out narrow alliances with people who will jettison them as soon as they are no longer useful.

Lucas wrote: “Political tribalism would likely scupper any moves that are just about putting Jeremy Corbyn in charge” – but despite his unpopularity among “the sensibles”, Corbyn remains the leader of the opposition and commands sufficient support within his party to ensure any challenger is seen off. No national unity gubbins can get past the fact that all roads to stopping Brexit run through a Labour government. Whether you believe Corbyn is pro-Brexit or not, he is against no deal, unlike Johnson’s cabinet. Remainers seem to understand that it would be awful if the decision put before parliament – or put to the public in a second referendum – was “Johnson’s deal v no deal”, but would seemingly rather try anything before making the choice of “Corbyn’s deal v remain”.

If it is so important that no deal is prevented at all costs, if this is not just all political posturing, then the “no Corbyns” sign has to come down off the treehouse.

• Phil McDuff writes on economics and social policy