The Conservative party is in the most desperate position that I can recall. It confuses office with power. It mistakes the EU referendum result for a party-political mandate. It assumes that the voters will sooner or later turn on Jeremy Corbyn as a dangerous socialist impostor. Its smile is really the rictus of internal paralysis.

'I'm not a quitter': Theresa May says she could fight another election as PM Read more

Since Theresa May declined to announce a plan for her resignation on the morning after the general election, two timetables have become fatally entwined. The first concerns the date of her departure: last week, she indicated that she aims to lead the Tories into battle in 2022, on the grounds that she is “not a quitter”. What else could she have said? This is the piqued response of her supporters when pressed on the manifest absurdity of the claim. And it is true that any prime minister who signals a date by which he or she will be gone – as Tony Blair did 11 years ago – is a lame duck thereafter. But May has been a lame duck since 10pm on 8 June, when the exit poll predicting the loss of her party’s Commons majority was broadcast. The problem is that the question “When will you resign, Mrs May?” includes its own answer: “Because you already should have.”The prime minister also referred to “getting Brexit right”, as though her decision to stay was justified by the negotiations that must conclude before Britain leaves the EU in March 2019, and by the government’s responsibility to preside over the outcome of those talks. Since her negotiating hand in Brussels was, by her own declared logic, weakened by the election result, this makes no sense at all.

Yet lurking beneath what she said last week is one of the Conservative party’s worst presumptions: that, irrespective of national mood or parliamentary arithmetic, it is always best placed to run the country and to represent its interests. I am genuinely baffled that so few of the Tories to whom I speak can see how arrogant this government now seems, and how terrible a price it may yet pay for its lack of humility.

Play Video 1:05 David Davis: €50bn Brexit divorce bill is 'nonsense' – video

It is true that there are echoes of 1996-7, the period in which John Major decided to play it long, hoping, like Mr Micawber, that “something will turn up”: the Blair bubble would burst, the economic recovery would be rewarded with votes, time would restore the natural Tory order. Instead, Major lost his Commons majority in December 1996, and then lost everything in May.

Now, as then, many Conservatives are in the grip of a collective delusion about what comes next: Corbyn will implode, the Brexit talks will remind the public of the need for grownups at the tiller, the fiasco of the election will be forgotten as (to coin a phrase) strong and stable government reasserts itself. Yet the party is in a bigger fix than it was 20 years ago. True, it is not fatally besmirched by “sleaze” as it was in the mid-90s. But its psychological state is much worse, and that is mostly down to Brexit.

Traditionally, Labour has been the party of teleology: convinced that history has a direction, that the dialectic of the struggle will lead to a preordained, glorious outcome. Now, it is the Tory Brexiters who have embraced this approach, interpreting Britain’s departure from the EU as a manifestation of national destiny, the unfolding of providence. Better trade, better wages, better borders, better trampolines, better tea cosies – you name it, everything will be better once we are free of the tyrannous grip of Brussels. Like all religions, this one tolerates no heresy. The relatively narrow victory of the leave campaign has been transformed from a mandate to be respected to a divine instruction from the burning bush. To voice the slightest doubt about any aspect of the process is to invite the charge of “remoaner”, and a cyber-lynching.

As so often, the ferocious defence of orthodoxy betrays structural weakness. This week, as the European Union withdrawal bill returns to the Commons, the government whips will be busily twisting arms to thwart amendments or rebellious cross-party cooperation. Their principal argument is that any such dissent will only smooth the path to a Corbyn government. But this is a disgracefully unpatriotic argument. Parliament has indeed voted to be bound by the referendum result. At no point, however, did it reduce itself to a rubber stamp, compelled by a single popular decision to surrender its collective critical faculties. It is precisely because Brexit is so important that MPs of all parties are obliged to scrutinise every detail of its implementation.

The fantasy that Brexit would be easy is costing us dear | Nick Cohen Read more

Mesmerised by the scale of its task, the Tory party is retreating into rank pettiness. More than ever, its impulse is to scapegoat rather than to reflect upon its shared responsibilities: the PM’s former chiefs of staff, Nick Timothy and Fiona Hill, were blamed for the election result, and their departure treated like the closure of a case in a cop drama.

Unfashionably, I think David Davis is making the best of a near-impossible job as Britain’s chief negotiator, and that the briefing against him reflects no more than a desperate quest for a fall guy. As he reiterated to the BBC’s Andrew Marr today, the talks are, of necessity, complex, hugely technical and marked by one “pressure exercise” after another. Would that some of his more starry-eyed colleagues acknowledged this so readily.

Pity a party that has the likes of Ruth Davidson, Amber Rudd and Matt Hancock in its ranks and yet is taking seriously the idea of Jacob Rees-Mogg as May’s prospective successor. What would once have been an amiable joke is now a measure of the Conservatives’ drift into an orbit of their own creation, the radio signal from Earth growing weaker by the day.

Yes, it really is that bad. To be absolutely sure that Labour forms the next government, all the Tories have to do is carry on as they are.

• Matthew d’Ancona is a Guardian columnist