Rishi Sunak's impossible task: sticking to a plan that Johnson doesn't have | Rafael Behr | Opinion

Tlast year it was hard to imagine anything ruining a chancellor's plans more than Brexit bothered Philip Hammonds. But it was another time. Hammond had not been exiled from the Conservative Party, no one had heard of the coronavirus, the supermarkets had enough toilet paper, and Rishi Sunak was a mere parliamentary deputy secretary of state in the ministry of Housing, Communities and Local Governments.

Sunaks' rapid rise to chancellor gives him status, not stature, and he enters his first budget with authority already diminished by the circumstances of his promotion. Sajid Javid resigned rather than handing over his Treasury advisers to a command and control structure based in Downing Street. By accepting the post on terms unacceptable to his predecessor, Sunak announced himself as the most submissive chancellor in memory of honor. If it has an independent streak, it keeps it covered in public. He is fluent in this polystyrene dialect that politicians use to fill the space in interviews when they prefer to say nothing. It is therefore difficult to distinguish between awkwardness and mediocrity. Sunak friends praise his intelligence, but for the stranger, he is unimpressive, which impressed Johnson about him. The Prime Minister knows that governments need competent managers, but he is also vain enough to prefer the mark of soft competence which does not encroach on his limelight.

The conservative chef is easily overshadowed by professional seriousness. This happens when he is flanked by the chief medical officer and chief scientific adviser to take stock of the fight against the coronavirus. Hearing Chris Whitty and Patrick Vallance talk about balancing risks, evidence, ratios and probabilities must be carried away from the jagged and roaring pace of recent British politics. Brexit banished the idiom of qualified expertise and it took an inevitable technical crisis for the experts to be recalled.

Johnson deserves credit for giving them the floor and showing deference in the process, even if it sets the bar low enough to congratulate a Prime Minister on knowing when to take science advice from his science advisor. This skill is remarkable only in someone known to have done the opposite. A deadly epidemic would question any administration, but in particular it tests the Johnsons team, because its default answer to any problem is to campaign against it. This is a consequence of the staffing of Downing Street with personalities from Vote Leave, the winning team from the 2016 referendum. This faction, led by Dominic Cummings, senior adviser to Johnsons, is adept at manipulating the debate and disorienting enemies with hostile frenzy. These techniques have a limited effect against a microscopic pathogen. The coronavirus will not be intimidated by an anonymous briefing.

The perpetual campaign plays on Johnsons' strengths as a communicator. He is a better candidate than a holder. Brexit has always sounded better as an ideological crusade, with clearly defined enemies, than as a technical project to manage. The implementation phase is boring, difficult and expensive, with no glitzy political gain, which is why Johnson avoids publicly joining the daily negotiations.

Brexit is both a symptom of ideology supplanting the pragmatism of the conservative party and a cause of the acceleration of this process. But Johnson himself does not have the consistency and discipline of a true ideologue. To prove his credentials as a true believer, he has to keep people like Priti Patel and Dominic Raab in high state positions. They are radical totem poles from the right, symbolically inflexible at the doors of the government, reassuring the faithful of the Brexiteer that their belief is correctly observed inside. But for the Treasury, Johnson prefers someone like Sunak an eurosceptic (he voted leave in 2016) but not a reactionary culture warrior or a fiscal disciplinary.

The Prime Minister wants a chancellor who is not stingy when there is political pressure to spend. The conservative manifesto has promised to balance the books by 2023, borrowing only for capital investment, but Johnson finds this budget belt too tight for his inflated rhetoric. He promised money for the NHS, schools, police, buses, flood defenses and a revival in underperforming regions. It is Sunaks' job to deliver this premium without increasing income tax, VAT or national insurance, the biggest levers of the Treasury for additional income.

It is a fairly high order even without the global economy showing symptoms of Covid-19 infection. The budget will propose to isolate businesses from economic contagion as the disease wreaks havoc on business and confidence. Emergency conditions provide a respectable cause for slackening of the belt so that markets do not shrink, but there is always a cost in credibility if a government folds new tax rules before they are never applied directly.

It is a Chancellor's job to provide a budget that supports the Prime Ministers' agenda, but it is also a function of the Treasury to resist Downing Street when economic facts diverge from government political discourse . Hammond played this role under Theresa May, and that made him a dissident in the Conservative Party. Johnson does not want dark figures that interrupt his optimistic narration. If he says the sun will shine, he doesn't need a Eeyore chancellor near the window pointing to the clouds. Giving the job to a bidding recruit is supposed to eliminate this problem. This probably only postpones a crisis, as tensions are inherent in the conservative manifesto that Sunaks' budget claims to implement.

Johnson wants to spend and build, but not borrow or tax. It promises Brexit dividends that won't magically appear on the difficult road it takes to Europe. He has reached the limit of what he can achieve in campaign mode, but he is not ready to make the painful choices the government needs. He was brought to power by zealous revolutionaries but is not one of them by temper. Suddenly, his government has the aggression of an ideological project but not coherence. He continues to build on his electoral victory, but that will soon run out. For now, the Conservative party is mostly convinced that Johnson is leading them to a promised land. Others can see that he has no idea where he's going.

Rafael Behr is a Guardian columnist