The Tory party has been hollowed out and filled with Boris Johnson's vanity

<span>Photograph: Reuters</span>
Photograph: Reuters

Tens of millions of people have already had a meal subsidised by the government. More will take advantage of Rishi Sunak’s “eat out to help out” policy before it ends next Monday. None of those diners is in doubt over the identity of their benefactor. The scheme has been marketed with the chancellor’s signature. His party gets a meagre portion of leftover credit.

Propping up restaurants with public debt is not typical Conservative economics, but the pandemic demanded ideological flex and Toryism is an elastic concept. That is the key to its historic success in winning and holding power. Sunak’s mastery of that adaptive method will serve his ambition well, and his ambition has an appetite.

The one Tory ethic that persists through every ideological mutation is the will to power

The chancellor understands that leaders need personal brands and how failure to craft one for yourself risks having one imposed by your enemies. “Dishy Rishi” will be happy to join “Boris” in the club of politicians on first-name terms with the electorate. That connection buys a lot of support among Tory MPs, mindful of how shallow affection for their party can be, and how deep resentment of it can run.

Fifteen years have elapsed since David Cameron first identified a need to “decontaminate” the Tories. He succeeded to the extent that Britain has had a Conservative prime minister for the past decade. But winning has involved a cycle of brand laundry that has bleached the party’s identity to a faint pattern, barely distinct behind the character of its leader. Boris Johnson then dyed it the deepest shade of Brexit.

A few Tories balked. Most embraced the change with sincere zeal or went along with it as the best strategy to close down the threat from Nigel Farage. MPs who once muttered in private that Johnson was unfit to be prime minister queued to serve in his cabinet.

In electoral terms, the gamble paid out handsomely. Johnson won big and, with the aid of a vote-repellant Labour leader, captured places that once recoiled from the Tory touch.

The party that now governs Britain is a weird chimera – a limp Tory body, fired by the imported spirit of Ukip (latterly, the Brexit party), with Johnson’s head hosting Dominic Cummings’ brain. Its doctrine is also a hybrid. Tories who think about such things explain Downing Street’s plan in terms of leftward tilts on economics and rightward slants on nation, culture and identity. The aim is to lock in the allegiance of voters poached from Labour by spending on some things (the NHS and infrastructure), while clamping down on other things (crime and immigration).

That trajectory is not very different from the one Theresa May had in mind but failed to pursue for want of time and parliamentary bandwidth. Johnson has the Commons majority. His problem is money. While Sunak is happy to borrow in spades for a pandemic response, the chancellor and other previously frugal Tories are reaching the limit of their tolerance for a fiscal free-for-all.

Without a blank cheque for marginal constituencies, Downing Street will rely on the constant mining of culture-war grievances to persuade people that Johnson is on their side, while a cosmopolitan, London-centric, “woke” Labour party is not. That would be more effective if Keir Starmer responded symmetrically, launching himself into culture wars from a radical left trench, which he shows no sign of doing.

Meanwhile, Conservatives who are attached to the idea of being in a party with its own history and values, as distinct from a band of pro-Johnson political mercenaries, have another problem: Cummings. The prime minister has maverick tendencies but a recognisably Tory style and instincts. His chief adviser does not. Cummings is unsentimental about venerable institutions. He despises the rituals and hierarchies that make a party. His cold-blooded utilitarianism is essentially un-conservative: old structures are presumed obsolete; their preservation viewed as indulgence that slows progress.

Tory MPs liked that attitude in Brexit rhetoric, but sensible ones get nervous when it turns to kicking indiscriminately at pillars of state and society. War on Brussels is a given. Opening a second front against Whitehall and the BBC gets riskier. Picking fights with the military, letting it be known that Cummings can “sort out” the chief of defence staff, starts to look megalomaniac. Loosening planning controls threatens civil war in the Tory shires. Where are the limits? It was one thing for the Conservative party to dabble in recreational revolution, to lift sagging electoral spirits, but MPs are now worried about addiction and overdose.

Related: Why are parents still scared to send their children back to school? Ask Boris Johnson | Simon Jenkins

There is a warning in the condition of the US Republican party, which this week adopted a policy platform of explicit, blind allegiance to Donald Trump. Nothing else.

Differences of culture and constitution diminish the comparison with American politics, yet there is a likeness in the way the Tories fell in thrall to a cult of incoherent nationalistic vandalism, called it renewal, and allowed their party to be hollowed out for use as a vessel to be filled with one man’s vanity. Last year Conservative MPs thought Johnson was their saviour. In time they may see him as a parasite.

They aren’t at that stage yet, not while the party is just about ahead in opinion polls. If that changes, the unravelling could be fast and messy. The one Tory ethic that persists through every ideological mutation is the will to power. Johnson delivered it, thus earning the right to mould what it means to be Conservative in his own image. But it is a thing without substance, a brittle shell around a void. It only looks solid in the hands of a winner.

• Rafael Behr is a Guardian columnist