On leaving parliament, Boris Johnson has decided to blame everyone for his downfall except himself. He accuses the privileges committee, with its Conservative majority, of being a “kangaroo court”. By extension, he accuses the entire House of Commons, with its Conservative majority, won under his leadership, of taking part in a “hitjob”. And he is too cowardly to face the voters of Uxbridge and South Ruislip, who gave him a majority of 7,000 votes at the last election. This is dangerous. The seriousness of the threat to democracy of Johnson’s conspiracy theory is masked by his buffoon act. But make no mistake: this attempt to deny the legitimacy of democratic procedures is like Donald Trump’s claim that the last US presidential election was “stolen”. Anyone can disagree with the findings of the privileges committee.

It could be argued that it didn’t need to investigate whether Johnson had knowingly misled parliament about lockdown law-breaking in Downing Street — he had already lost his job as prime minister, mainly because the public, the Commons and his ministers felt he hadn’t been straight with them on the subject. It could be argued that a 10-day suspension, opening the way to a by-election in Uxbridge, was too severe. But to suggest that the committee is “anti-democratic”, and that Harriet Harman, its chair, is guilty of “egregious bias”, is quite different. As chair, Harman has a casting vote that she uses only if the other members’ votes are tied. So the committee could have found against Johnson only if one or more of its four Conservative members (Andy Carter, Alberto Costa, Sir Bernard Jenkin and Sir Charles Walker) did so. The truth is that Johnson is bad at politics, and that he lost the confidence of too many of his own party. By lashing out at imagined plots against him, all he shows is a narcissistic destructiveness intended to bring down a government of which he is no longer part.

No one did anything to him that he didn’t do to others: he voted against David Cameron and resigned as a minister in a way that weakened Theresa May. His statement announcing his resignation as an MP was intended as a declaration of war, but is in fact an admission of defeat. Even so, the Tory Samson can still do a great deal of damage to the party on his way out. Three by-elections, in Uxbridge, Selby and Mid Bedfordshire, are not going to do the government any good. Labour should win in Johnson’s former seat, despite that poll by Lord Ashcroft suggesting that Johnson himself could hold it (and Johnson won’t be the candidate, in any case). And the Lib Dems should be able to repeat their successes in coming from third place in North Shropshire and Tiverton and Honiton in the “safe Tory” seats of Selby and Mid Beds. These could be written off as protest votes. Rishi Sunak may even try to present them as backward-looking protests against Johnson and his lockdown hypocrisies. But they make it harder for Sunak to claim to be steadily recovering lost ground.

One former cabinet minister told me this week that he thought the Tory party was not yet ready to give up and “abandon all discipline”, as it did in the final years of John Major’s government, and as Labour did in 2009-10. But three by-election defeats will not help Sunak. The main effect of Johnson’s temper tantrum this week, then, is to increase the likelihood of a Labour government — for which the Conservative Party should judge him harshly. The secondary effect is to corrode the assumptions on which parliamentary democracy rests. If a significant part of Tory opinion becomes even more Trumpian, regarding the House of Commons as a conspiracy against the “one true Conservative path”, that is dangerous.

Serious as the threat is, however, I think Johnson is finished and won’t succeed in his attempt to destroy parliamentary democracy. Even if there are further hostile resignations triggering by-elections the Tories will lose, I doubt if they will provoke a Tory civil war. Johnson is too ideologically inconsistent to inspire for long any of the subcultures of party opinion — not the Trussite tax-cutters (he was a big spender); not the anti-immigration Bravermanistas (he is pro-immigration); and not the Spartan Eurosceptics (“real Brexit hasn’t been tried” is a slogan of limited appeal, even in the Conservative Party). The healthy choice for the Tory party would be for it to allow the waters to close over Johnson’s head, and to recognise that he will not return. In the end, British democracy is strong enough to bend and bend back.