Battlelines have been drawn between one of the most searched-for couples on the internet and Britain’s media: #TeamMeghan versus free speech fighters of the press. Prince Harry has filed legal proceedings against Britain’s two biggest tabloid newspaper groups for phone hacking and concealment, while his wife has sued the Mail on Sunday for publishing a private letter.

This all-out assault on the powerful tabloid press by a member of the royal family has been a long time coming – nine months since the Duchess of Sussex’s letter to her father was published in the paper, and 22 years since her husband’s mother died in a car crash, pursued by paparazzi.

It is set to be a landmark legal challenge, not because it breaks new ground in privacy cases, but for the line it seeks to draw in the sand between the modern monarchy and the media. It will probably be nasty, brutish and, with the phone hacking case not coming to trial for a year at least, not particularly short. Wherever your sympathies lie, there are also unlikely to be any winners.

Part of the problem is that proper debate on a case-by-case basis no longer seems possible. For every social media post pointing to the sexism and racism underpinning much of the criticism of Meghan, there’s another attacking the couple. Not just posts, but the entire front cover of the Spectator’s first US edition, in which Rod Liddle urges America to “take Meghan back”.

Meanwhile, royal stories with a proper public interest – such as Prince Andrew’s relationship with Jeffrey Epstein – are pushed off the news agenda.

Harry has made clear via a statement on a website apparently set up for the purpose of bypassing the media that he is fighting historic injustices that still persist, despite the millions lost in readers and revenues since his mother died. “In today’s digital age, press fabrications are repurposed as truth across the globe. One day’s coverage is no longer tomorrow’s chip paper.”

No one likes to prejudge a lawsuit – especially a journalist – but Meghan’s claim of misuse of private information, infringement of copyright and breach of the Data Protection Act is likely to prove difficult for Associated Newspapers – publisher of the Mail papers and MailOnline – to win. Respect for family life is at the heart of article 8 of the European Convention on Human Rights. Its first line reads, “Everyone has the right to respect for his private and family life, his home and his correspondence.” A handwritten note to your estranged father seems to tick “private”, “family” and “correspondence” all at once.

Mail lawyers are likely to argue that, as the letter was first mentioned in a People magazine article sympathetic to Meghan, her father had the right to reply. This would surely have justified an interview, but not so many extracts and discussion of her letter.

On the issue of copyright, which everyone accepts Meghan owns, there is no public interest defence at all. The Mail on Sunday should know this better than most as it lost the last time a royal sued for the publication of private letters – in that case, Prince Charles’s “diaries” from an official trip in 2005. However, the newspaper group said it “stands by the story it published and will be defending this case vigorously”.

On the wider hacking and concealment case, there has been little official comment. Lawyers for both the News and Mirror group newspapers are trawling the welter of cases since 2009 to prove alleged email deletion does not constitute the industrial scale cover-up alleged.

Whatever the verdict, the huge cost of fighting these cases could still end with a win of sorts for the press. If they go to trial, the Sussexes could be the first royals to appear in court in person in more than a century. Imagine the coverage.

This comes as the monarchy is increasingly mired in a constitutional crisis over Brexit, and the media’s role in holding the powerful to account is itself being increasingly questioned. Mark Stephens, the media lawyer, saw two distinct parts to Meghan’s Mail on Sunday complaint. “They [the Sussexes] have picked a battle they are going to win. But the press release also picks a war which is foolish, hasty and ill-advised.” Not just for the Sussexes, but for society as a whole.

This is where cooler heads should prevail. Everybody, including members of the royal family, deserves a private life and the chance to define that privacy. But it is possible to be “Team Meghan” and still think it acceptable to question the cost to taxpayers of royals renovating their home, or taking four private jets in 11 days. This is not the press protecting their own, even those who behave badly, but an essential defence of what journalism is – holding the powerful to account. The fact that a mixed-race woman has come in for way more than her fair share of such questioning is revolting when put against the lack of coverage of other royal stories, but that doesn’t stop at least some of the questions being legitimate.

So much has changed since pictures of Diana in her gym kit were taken secretly and published in the Mirror. She sued and ended up settling out of court. Yet so much has also stayed the same. Some privacy campaigners argue that the current state of the relationship between the young royals and the media is a sign of the press newly flexing its muscles after years in a post-Leveson straitjacket.

One or two questionable stories do not hide the fact that press behaviour has changed, albeit too little for some. Saying otherwise risks turning any story about the press into the sort of social media rant from which most of the industry likes to distance itself. It’s hard not to agree with Harry’s statement: “Media freedom and objective, truthful reporting is a cornerstone of democracy and in the current state of the world we have never needed responsible media more.”

Johnson family values

My mind started to wander during Boris Johnson’s speech at Tory party conference last week, as I fear did his. But it gave me a brilliant idea – not how to get us out of the current quagmire, sadly, but a new show for the screenwriter Jesse Armstrong.

When Johnson revealed the “ace up his sleeve” – that his mother, the daughter of a former president of the European Commission of Human Rights had voted for Brexit – it seemed a perfect follow-up to Armstrong’s brilliant TV show Succession, about a madly dysfunctional media family with so many similarities to the real-life Murdochs. Just imagine: the warring, photogenic children, the artistic mother with a secret and the colourful father. I even thought of a name: Blond Ambition. Come on, it’s better than thinking about Brexit.