I am not sure there is agreement on what a culture war is but for me it is not simply disagreement over a policy or idea, or even heated disagreement, but the kind of disagreement which does not allow for compromise or acceptance that the other side has a point. As such you are not just arguing about x or y but there is something more at stake in terms of identity, including party political identification, going on beneath the surface. To be a culture war and not simply a skirmish, the argument needs to be taken up by large groups of people in society – something that tears families and friends apart. 
The best example, we had in UK of a full-on culture war in terms of scale and refusal to listen to the other side was the Brexit referendum. However, over time Brexit has lost its potency: many of those that voted remain have reluctantly accepted they lost the vote, and many of those that voted leave see little to revel in. Of course, we do have culture skirmishes on topics such as taking the knee, taking down statues of civic leaders involved in the slave trade and what should be included in the school history curriculum. These are all important issues, and anyone offering forthright views might be pilloried on social media and, if high profile enough, subject to hate mail and worse, but most of these skirmishes have not really hit home beyond supporters of different positions, at least not on the same scale as appears the case in USA. Two examples of this less fevered atmosphere are vaccinations (over which there is a huge consensus that they are good thing) and mask wearing which is supported by voters of all parties in more or less equal measure, though supporters may differ a little on the reasons they do so. 
This talk of culture wars is by way of reviewing Jon Ronson’s new series ‘Things fell apart’. Ronson’s niche as a journalist is dealing with off the wall opinions, often beliefs in conspiracy theories. When presenting he is is ‘faux naif’; he is rarely shocked, more curious, about why people think such outlandish things with such apparent conviction.
To give a flavour of Ronson’s earlier work, have a look at his documentary on David Icke 
Icke was a minor sports commentator in UK but achieved notoriety in the early 1990s when he took the mantle of ‘son of the godhead’ upon himself and made apocalyptical predictions about the disasters about to befall the earth. Later, he offered more off-the-wall ideas including, reportedly, the idea that reptilian beings had taken over leading positions on earth. Ronson followed Icke on a tour of Canada and while his stance is not sympathetic Ronson does not mock in the way that Icke was routinely mocked by most commentators. Reflecting later on conspiracists, Ronson became more concerned by their psychopathic behaviour but this did not stop him recognising the following they attracted. Writing in 2021 he noted:
… there was something that the mainstream media, in its hubris, failed to notice about David Icke: a growing number of people were feeling more aligned to him than to his tormentors. These were people who also, for their own reasons, felt ridiculed and shut out of the culture. And so when Icke re-emerged with his paedophile lizard theory he immediately began selling out concert halls across the world. It was an incredibly surprising and, I suspect, spiteful story born from injury: conspiracy theory as grievance storytelling. And it was a dangerous theory, with its appeals to paranoia and delusion. 
In this present series on BBC radio  Ronson is building on his work in the field of conspiracy theories to ask when did issues that should have been questions of reasonable debate become toxic, in other words when did arguments about school textbooks, abortion and today vaccination against Covid and mask wearing become part of a culture war? This leads him to the USA and in the first of his series he covered the abortion debate.
It was surprising to me and I guess to most of his UK listeners to find that abortion was not a key concern of evangelical Christians in the 1970s or even at the time of the Roe v Wade case back in 1973. As Ronson explains abortion was very much catholic territory but this changed and one key player in making this happen was Frank Schaeffer. Perhaps Ronson is bigging up Frank’s influence, but it is a good story nonetheless. Schaeffer produced a film for his father, Francis, to illustrate his grand opus on belief and civilisation, ‘Should We Then Live: The Rise and Decline of Western Thought and Culture’. The film ended up as a ten-part series looking at large themes of art, history and culture. As a film it is low budget and clunky, especially so after all these years, but it has to said by and large it works. There is a lot of talking to camera but the backdrops change and documentary footage is frequently spliced in dramatic effect (not sure if there were copyright infringement here but never mind). Francis comes over as stern and unyielding as a narrator but speaks clearly; he does not rant and rave, and he has a genuine interest in art and civilisation. What particular appealed to evangelical audiences was that he was saying it was alright to be interested in culture and so gave religious belief some gravitas and a sense of higher purpose. That said, the films are, from my point of view, largely propagandist and the relentless message is humanism (in Francis’s view the mistaken idea is that we all have a right to express our agency, and the right to use reason to set out laws to address the problems of the day) is failing, we should get back to the word of God to regulate our affairs. 
Ronson is interested in these films as abortion is thrown in towards the end of the series as illustrative of the perils of secularism. Apparently, its inclusion had come about as Frank had linked the ‘pro-life (or anti pro-choice)’ argument with his own experience of having become a father, rather than any insistence from Francis. The film was shown to large evangelical Christian audiences in USA as well as countries in Europe. Frank had a keen eye for publicity to trigger initial interest and after that it became a a word-of-mouth phenomenon.
‘Should We Then Live’ was followed up with the much less popular ‘Whatever Happened to the Human Race?. This differed in that the anti-abortion stance was laid on with a trowel. There were repeated images of gurgling babies contrasted with gruesome images of dolls floating around in the Dead Sea to represent aborted foetuses. According to Frank he had to push and push to get evangelicals to take notice of the film and they only did so when it had generated sufficient controversy. This led Frank to take the ‘credit’ (in inverted commas as he came to regret his stance and disowned the evangelical movement) for tying in anti-abortion positions to evangelical Christianity.
It seems clear that Francis and Frank Schaeffer played a part in making abortion a left-right issue but others point to baser political concerns. Jimmy Carter was standing for re-election. As it happened events in Iran scuppered his chances but this was not to be known at the time and opponents were looking to drive a wedge between the liberal Carter (who described himself as a born-again evangelical Christian) and evangelical voters. Abortion was the issue to do this and it was pursued relentlessly by Republican strategists iin the service of Ronald Reagan, the republican challenger who ironically had enacted some of the most liberal abortion laws as state governor in California. Increasingly from then on abortion became a toxic political issue .
Ronson is a good story teller and the idea of understanding how culture wars began is a good one: we need to remember when it became normal to refuse to listen to the other side. What we learn is that culture wars did not begin with the internet but were always there. Abortion became an issue of political identification through using old style media, interest group networks, print advertising coupled with party political manipulation. Maybe divisions later became amplified by social network algorithms and online echo chambers but the process is not inevitable. The conditions existed for abortion to be a touchstone issue in England (it remains so in Northern Ireland) but it did not happen. Of course, this might all change, but we need sociological and political explanations as well as technological explanations to explain how and why they do.
 Writing about his stint as Washington correspondent the BBC correspondent Jon Sopel started by mentioning the things he most liked about living in the USA but then commented on growing culture wars in US. He felt that the list of of no-go topics for the thanksgiving dinner table is now so extensive, that many families have simply decided it is better to call the whole thing off https://www.bbc.co.uk/news/world-us-canada-59395804
 See Chris Anderson and Sara Hobolt (2020) No partisan divide in willingness to wear masks in the UK
 The Secret Rulers of the World – David Icke, The Lizards and The Jews – Jon Ronson was broadcast 6 May 2001 it is to that easy to find but try https://www.youtube.com/watch?v=HBMw2QErYzs
 Things Fell Apart available as a podcast on BBC and other outlets https://www.bbc.co.uk/sounds/series/m0011cpr
 This is from Channel 4 in UK but not difficult to track down on YouTube and other networks.
 Jon Ronson (2021) Making sense of conspiracy theorists as the world gets more bizarre, The Observer, 11 April, 2021
 How Should We Then Live (1977) is easily tracked down on YouTube and other outlets
 See Luis Josué Salés (2021) Christian attitudes surrounding abortion have a more nuanced history than current events suggest, The Conversation, 13 July 2021 7]