What does the Conservative party stand for in 2019? If you survey the central tenets of Tory ideology from the past 50 years, it is hard to find a single one that is still intact.

The party of business is hellbent on undermining access to an export market of half a billion people. The party of law and order is now raging against the judiciary – with senior Tories being regularly asked whether their government intends to obey the law.

The party of “family values” – “back to basics”, as John Major put it – has now fallen for the charms of a famous philanderer, who is currently being dogged by questions about how his “close friend”, Jennifer Arcuri, was awarded £126,000 of grants during his time as London mayor. The party of the establishment is provoking a constitutional crisis, angering the Queen and expelling some of its most distinguished MPs from its benches.

So perhaps the more pertinent question is whether there is anything the Conservative party won’t stand for. But the answer to that isn’t much clearer: the Johnson-Cummings strategy depends on cultivating the sense that they will say or do anything to achieve their ends; their only principle is a refusal to rule anything out. And to the extent that they face any constraints, these are not coming from inside the Conservative party.

The Conservatives are now to the Brexit party what cocaine is to crack: more acceptable in polite company, but ultimately made of the same stuff

Surviving Tory moderates kid themselves that the problem is all with Boris Johnson’s chief adviser, Dominic Cummings, as if they hadn’t fallen into line behind a man famed for dishonesty and recklessness. They kid themselves that the party is still theirs, as if it hadn’t swelled with Brexit fanatics with no interest in governing. The fact that Amber Rudd resigned simultaneously from the cabinet and the Conservative whip clarified the stakes: the current toxicity belongs to the party, not any individual strategist or leader.

For a party that had been losing its political and philosophical moorings for many years, Brexit has become a substitute for ideology – something more potent and emotional than just a vision for a good society or a policy manifesto. For Conservative party members and many MPs, Brexit is almost theological: it is a crusade requiring sacrifice and suffering. It is not possible that the reality of Brexit will ever live up to the divine version, while parliamentary democracy now appears hopelessly compromised in comparison with the pure “will of the people” that the 2016 referendum is believed to have revealed.

This fanaticism is being escalated and exploited by men without any apparent ideology of their own, or even any particular faith in Brexit. On the actual question posed by the referendum, Boris Johnson was famously ambivalent. And after writing tens of thousands of words about British politics on his own blog, it’s still not clear how Cummings really thinks society should look, or if he even identifies as a “conservative”. These men are opportunists, for whom nationalist fervour and chaos provide an opening to seize power. And a party in the grip of collective mania is more vulnerable to such machinations than one with a coherent ideology.

To pinpoint the origins of this ideological decline, one has to look back much further than the referendum. The identity and purpose of the Conservative party has been slowly unravelling for three decades. The year of the “big bang” was 1986, when the City of London was dramatically deregulated, disrupting the old boy networks of Britain’s business classes with the shock of a new, aggressive style of international finance. The subsequent explosion of wealth opened up a cultural and financial schism between London and England – sowing seeds of resentment in the shires that would blossom in 2016.

But 1986 was also the high point of Tory Europeanism, the year of the Single European Act, which set Europe on the path to a single market, and was driven and crafted by Margaret Thatcher and her allies. Before this point, the crusade for “free markets” was an ideological rallying cry for the new right backers of Ronald Reagan and Thatcher – a soaring ambition that could only be brought to fruition by brave leaders in their mould. Now it would become a technocratic and regulatory project, overseen by bureaucrats and lawyers. With the demise of state socialism three years later, capitalism no longer needed the Conservative party. And business soon found a better friend in New Labour – which offered state-of-the-art regulation and a culture of innovation – than it has found before or since.

Margaret Thatcher and Ronald Reagan walking his dog, Lucky, on the White House lawn. Photograph: Bettmann/Bettmann Archive

Over those 30 years, there was one force in Britain’s public life that never gave up on the Tories: the press. All those resentments that took the place of conservative ideology – the loathing of multiculturalism, Brussels, Blairism, immigration, and the vast riches being made in London – were given a safe space in the pages of the Daily Mail, the Daily Express and the Daily Telegraph. With their constant attacks on all symptoms of liberal globalisation, these papers provided the incubator for the rage currently sweeping British politics, during the long years when national borders and rural England were out of political fashion.

With one of those newspapers’ favourite sons ensconced in No 10, the boundary between the opinion pages and Westminster has dissolved. The resentments that had brewed for decades – towards “political correctness” and the milieu of metropolitan graduates – now flood public life, with the arrival of a prime minister who speaks his mind as recklessly at the dispatch box as he once did on the page. What these forces of reaction stand for is not “free markets” or “private enterprise”, but the sort of back-scratching, long-lunching privileges that once made the establishment tick.

The collapsing division between Conservative party and conservative press has produced an optical illusion in which the concerns of the party are constantly mistaken for those of the country. One of the curiosities of David Cameron’s recent round of memoir-promoting interviews was his complete inability to distinguish between “Europe” as a problem facing the nation (where fewer than 10% of the public deemed it to be an important issue, right up to 2016), and Europe as a problem ripping through the Tory party.

No explanation of Brexit – and hence of the worst political crisis in living memory – can escape the truth that it was born, nurtured and released into society from the Conservative backbenches. The party has done for British democracy what derivatives did to the financial sector – and it has so far survived the carnage it produced. Instead, blame for the chaos has been sprayed in all directions: on to Europeans, Labour, remainers and “the elites”, thanks to the symbiotic relationship between party and press.

Johnson could win a workable majority in the next few months. And yet there’s a marked absence of triumphalism in the party. The current poll lead feels precarious; 59% of Tory members have already voted for the Brexit party once (in the European parliament elections), and many could well do so in future. The Conservatives are now to the Brexit party what cocaine is to crack: more acceptable in polite company, but ultimately made of the same stuff.

Rage and resentment are powerful political forces, but dangerously unpredictable. Unlike a newspaper columnist, a prime minister takes far more flak than he dishes out, and Johnson now appears harried and uncomfortable. Lacking any positive vision of the economy or society, he and Cummings are entirely reliant on channelling resentment towards various foes, from supreme court justices to Jeremy Corbyn. The newspapers will do their bit by escalating the attacks.

But these nemeses cannot soak up all that anger indefinitely. The forces behind Brexit will need new scapegoats soon – and Johnson, Cummings and the Conservative party could be next in line.

• William Davies is a sociologist and political economist