Conventional wisdom has a remarkable capacity to recover from the many batterings it receives and carry on as if nothing has happened. Like Doctor Who, it doesn’t die but regenerates.

Last week, it was anticipating the defeat of the populist right – that combination of opportunism, utopianism, victimhood, wilful ignorance, conspiracism and racism, for which we do not yet have a satisfactory label. Even though Theresa May’s government is collapsing as if it has been hit by a wrecking ball, even though her withdrawal agreement has been defeated by the two of the largest majorities ever, conventional wisdom assures us that the Brexit ultras must support it on her third attempt.

May’s deal is “back from the dead”. The right must realise the choice now is between May’s deal or a soft Brexit or no Brexit. The crisis will pass as it falls into line.

Taking the smallest of steps away from Boris Johnson and Jacob Rees-Mogg, commentators point us to the diminished figures of Nigel Farage and his former accomplices in Ukip. Farage is now leading a party no one has heard of, they say, while everyone agrees that Ukip has consigned itself to the fringe by becoming a nakedly anti-Muslim outfit.

Yet hush their chattering and you hear a howling from the right that’s stronger than ever. Little noticed amid the chaos in parliament were the 202 politicians who proved their unfitness for public life when they voted against allowing May to ask the EU to extend the deadline for leaving. An extension would not even have ruled out the catastrophe of crashing out with no deal, if that was what was bothering them. Britain could still topple over the cliff at the end of it.

Rather, the 202 MPs, 188 of them Conservatives, were voting against the very notion of diluting the purity of Brexit. My colleague Rafael Behr recently wrote of Johnson and Rees-Mogg: “Grievance is the raw material they need to fuel their politics.” They will never abandon it or take responsibility for the disaster they have brought on their country. In their minds and the minds of millions they represent, they are victims rather than perpetrators. Owen Paterson, a know-nothing and learn-nothing politician who nevertheless served in David Cameron’s cabinet, declared: “To the horror of the political establishment, the commercial establishment and the media establishment, the people have gone against their will.”

It is an exaggeration to describe as “fascist” the fantasy that democracy as represented by parliament, the whole of the media, including the rightwing press that nurtured Brexit for decades, and business are a part of a vast conspiracy against the cheated people. But it is pre-fascist in its sweeping assertion that rottenness lies everywhere except on the honest right, which alone represents the people’s will.

As always, opportunists bend before the prevailing wind. The worst type of Tory politicians know they must please their base. On Thursday, the Conservative MP Stephen Crabb met a colleague who told him article 50 must be delayed. “I asked him why he voted against it then. ‘I have my association AGM coming up,’ he replied.”

Facebook Twitter Pinterest Nigel Farage in Sunderland before the start of his ‘Brexit Betrayal’ march to London. Photograph: Scott Heppell/Reuters

Meanwhile, Farage isn’t a marginalised but a leading figure in a rightwing version of the 20th century’s Communist International. Last week, he was asking his comrades in populist EU governments to veto any extension to article 50. His moneyman Arron Banks and mouthpiece Andy Wigmore went to Italy to take the message to the governing League party, while Tory MPs made the same arguments to Poland’s Law and Justice government. Lobbying foreign powers to overturn the decision of the British parliament is, to use the language of the right, close to treasonable. But no one can be sure they will fail. After receiving her friends, Anna Maria Anders, the Polish minister for international dialogue, opined that she was “definitely against deferment and another referendum”.

However convinced you are that Brexit is a historic mistake, do not slip into the error of believing that the EU is a model of enlightened government. It is a battlefield. And as far as authoritarian governments in eastern Europe and Italy are concerned, Farage is their ally. Given his friendship with Trump, who, right on cue, was criticising May’s handling of the Brexit negotiations last week, his apologias for Putin and his associates’ alliances with the Russian embassy, I can make a case that Farage has as much influence as our foreign secretary, whoever he may be.

As for Ukip’s Islamophobic turn, I would not count on that guaranteeing its irrelevance. The lesson of recent history is what the extremes do one day the mainstream does the next. The Tories have taken Ukip’s Europhobia. Labour has taken the Communist party of Britain and the Socialist Workers party’s tolerance of anti-western tyrants. Who is to say that tomorrow’s Conservatives won’t be aping the Islamophobes in today’s Ukip? Boris Johnson has already tipped enough winks that he’s happy to accommodate them.

Which brings me back to where I started, with the cheery cries that the Brexit crisis may just be for Christmas and not for life; that May’s withdrawal agreement will get through and we can “move on”. The sentiment is vacuous. There’s no guarantee that May’s agreement will be approved. Even if it is, the real business of negotiating a trade agreement will then begin and reignite all the old divisions.

Worse than the practical considerations is the abject failure of the political class, most notably of the leaders of the Labour party, to challenge the right where it matters most in the battle for voters’ minds. The myths of Brexit survive. Workers whose living standards and services will be cut and jobs lost have never heard the leaders of the party founded to represent them deliver a full-throated demolition of the false promises Farage, Johnson and their friends sold to 17.4 million people.

Whatever hopes conventional commentators place in parliamentary manoeuvres, the unyielding truth remains: you can’t win battles without fighting them.

• Nick Cohen is an Observer columnist