Spite. When you dig down to the essence of modern rightwing politics, you’re left with little else. This wasn’t always the case. Margaret Thatcher and Ronald Reagan offered clear, coherent visions of society, even if their worship of free markets delivered economic insecurity and stagnating living standards. While today’s Tories and Trumpified Republicans remain committed to defending privileged interests, their driving ambition now seems to be deliberately provoking fury among the progressively minded, much to the delight of their supporters. It’s this tendency that led Donald Trump to denounce Mexicans as criminals and attempt to ban Muslims from entering the US; it’s the same tendency that drove the home secretary, Suella Braverman, to declare that her “dream” and “obsession” was to see a flight transporting asylum seekers to Rwanda. Cruelty is precisely the point.

But this spite has found a particular target in younger British and American people, many of whom increasingly embrace progressive social values such as anti-racism and LGBTQ+ rights (granted, this relies on a generous definition of youth as millennials – while the oldest members of Generation Z are only in their mid-20s, the most senior millennials have now reached their early 40s). These generations have become a common enemy for the right. The feeling is mutual. According to new research and survey data, millennials are defying a supposed iron law of politics, that we shift to the right as we age. No other generation in recorded political history has retained such an entrenched rejection of rightwing politics as they’ve grown older.

The right has become its own gravedigger for two reasons. First, by building an economic model that promised individual freedom but delivered mass insecurity; and second, by intentionally and repeatedly insulting the social values of the young. British culture fetishes home ownership even while its economic policies make this an increasingly distant dream for younger citizens. Young people have also borne the brunt of austerity, being saddled with university debt and suffering the closure of youth and Sure Start centres. Yet a generation that is more educated than ever but simultaneously deprived of prospects is treated with unadulterated contempt by the right. It is, after all, labelled the “snowflake generation”, which the Collins English Dictionary has defined as “the young adults of the 2010s, viewed as being less resilient and more prone to taking offence than previous generations”.

On both sides of the Atlantic, the right fears a younger generation of economically insecure and socially progressive citizens. Commentators and politicians treat younger people as woke barbarians at the gates threatening to tear down everything conservatives hold dear. The moral panic over so-called “cancel culture” is a striking example of this: what it really boils down to is an attempt by millennials and zoomers to assert their progressive social values and reject the bigotries found among some older Britons and Americans. “Millennials are the silencing generation,” complains the rightwing Wall Street Journal, denouncing them as “perpetually offended” (what this perhaps really means is that younger people are less keen on demonising migrants or obsessing over the existence of trans people). “Millennials were woke enough … but the next generation is much worse,” cries the Telegraph, denouncing university students as “Stalinist foot-soldiers”. Younger people are more likely to defend the rights of the minorities bullied and harassed by rightwing politicians, and conservatives hate them for it.

And so the British and US right have apparently condemned themselves to a political doom loop: savaging the progressive values of younger generations, and in doing so driving them further into the arms of the left. This bile may serve a short-term political purpose in rallying the core vote of the Tories and Republicans, but it seems that conservatives have thought little about what will happen as younger generations come of age politically and culturally. Perhaps rightwingers believed that the historic precedent of voters shifting rightwards with age would automatically assert itself, however much the young remained locked out of the prosperity their parents had enjoyed. What’s intriguing is how rightwing politicians and commentators alike have doubled down on poisonous invectives that alienate young people. Perhaps this is evidence of a fatalism: they know their fate is sealed, so nothing is to be gained from restraint.

As a case in point, last week a British rightwing shock jock announced that she’d choose the life of professional misogynist Andrew Tate “over the life of a half-educated, autistic, doom-mongering eco-cultist” Greta Thunberg. Her use of autistic as an insult was indicative of an increasingly vicious rightwing culture, but the unapologetic loathing towards Thunberg – whose offence is to seek to prevent humanity from destroying itself – was revealing. Thunberg has become emblematic of progressive younger generations: the bile frequently directed at her speaks to a hatred and fear of those whom she is seen to represent.

In building and benefiting from an economic model that has left younger people bereft of a secure future, and repelling them with a “culture war” against progressive values, British and US conservatism seems to be authoring its own demise. Young people voted for Margaret Thatcher’s Tories in the 1980s, but little over a fifth of voted for the party in 2019. While young Americans flocked to support Reagan in the 1980s, today their political icons are Bernie Sanders and Alexandria Ocasio-Cortez. The political right has treated the young as the enemy within. It may soon realise what bitter harvest it has reaped as oblivion awaits.

• Owen Jones is a Guardian columnist