He lied. He clearly lied. But so what? As Boris Johnson hangs on by his fingertips, we wait to see who will stamp on them. The answer is presumably Sue Gray, to whose final mercies he has desperately handed his fate. Surely nothing she says can rescue him. At question is not his guilt, only his punishment. Johnson can plead that he was “advised” that office parties were within the rules. He can protest they were “implicitly” work-related, but with even more revelations about Downing Street parties on the front pages today, the edifice of Downing Street concealment and deceit is crumbling before voters’ eyes. In that uniquely British political theatre, the House of Commons, the prime minister was subjected on Wednesday to the nearest democracy gets to medieval trial by ordeal. MPs abandoned all dignity, nuance, sympathy or sense of proportion. They gleefully yelled and jeered and hurled insults until hoarse with rage. When in the mood, parliament does not talk truth to power: it screams in its face. The prime minister’s unhappy relationship with the truth is longstanding and embedded in his character. Veracity is trumped by ego. Most of his recent catalogue of woes – Brexit promises, dodgy peerages, sleazy colleagues, flat decorations, lockdown parties – could have been soothed had Johnson simply come clean early on, appeared frank and apologised. He seems psychologically unable to disentangle falsity from half-truth. A life spent in bland denials and upmarket jokes has lent him a high-risk belief in his invulnerability. From each laughable lie he could, in one bound, leap free. Champions of political mendacity make much of its role in democratic leadership. In his study of political hypocrisy, David Runciman argues that fake sincerity, false promises and the fabrication of evidence are tools that have always lain close to the heart of power. He cites leaders from Oliver Cromwell and Thomas Jefferson to Bill Clinton and Tony Blair. The last fought the Iraq war on a lie. Peter Oborne’s The Rise of Political Lying has Blair’s spin doctor Alastair Campbell as its virtual hero, with his boss plumbing constant depths of mendacity. Yet Blair won three elections. Party manifestos are dismissed as “books of lies”. Some would argue that Johnson won the Brexit referendum by the “big lie” of its economic gains, which played much to his advantage at the 2019 election. Runciman argues that democracy requires a degree of cynicism to fuel its optimism, its promise of eternal hope, without which no one would ever vote for any politician ever. Politics thus becomes a mutual conspiracy of mendacity. As Orwell wrote, “Political language … is designed to make lies sound truthful and murder respectable, and to give an appearance of solidity to pure wind.” Johnson’s problem has not been his lying but his inability to manage it, notably when found out. He has no spin doctor, and on Wednesday had to admit himself to spin A&E. His belief that a winsome and “authentic” personality could make up for a rotten command structure and third-class aides exploded on him. His critics might accept that governing a pandemic would be a titanic test for even the most experienced of leaders, requiring superhuman skills of authority and persuasion, an ability to call on an unprecedented degree of public trust. But that is all the more reason not to imperil that trust. The prime minister has delivered some successes, including vaccination and the current holdout against lockdown. But these successes have been swamped by one fiasco after another, leading to a widespread judgment that he is “not fit for purpose”, not up to the job, a charge never made against Blair. A BBC vox pop on Wednesday night was brutal: “I may like him, but enough is enough.” Johnson has tried to fuse Alexis de Tocqueville’s distinction between Britain’s democracy of the club and America’s democracy of the mob. His appeal to the Tory club has lain exclusively in his popularity with the mob. He won elections as a populist. It is conceivable that a newly chastened and apologetic Johnson might try to charm his way back into favour, in the hope that the 10 percentage points now separating Labour from the Tories in the polls might be reversed. Club members might then hold their noses and give him another chance. As it is, any such poll surge seems most unlikely, which is why Keir Starmer is surely unwise to shout for the prime minister’s resignation. He should pray for him to limp on. For Johnson, an ominous parallel is the Tory party’s ruthless ejection of Thatcher in 1990. It cleansed the Downing Street stables of the poll tax toxin, and went on under John Major to win a fourth election in a row in 1992. If, as seems likely, Johnson’s days as a politician are now numbered, Britain’s brief excursion into populist politics will have ended. The moral of the story will be modest: that journalists, for all their vanity, should not be tempted to give up the day job. Simon Jenkins is a Guardian columnist