The engagement of Prince Harry and Meghan Markle is great news. Great news for them, of course, because they are clearly in love, and who doesn’t like to see a handsome young-ish couple in love? And it’s great news for republicans like me, too, because it confirms the monarchy has now completed its transformation from a mystical, godly outfit into a celebrity enterprise, which I’m convinced will prove to be the final nail, or one of the last nails, in the coffin of this archaic institution. Harry and Meghan, we salute you! (Metaphorically, not literally. Republicans don’t do that.)

In the coming days, the press will likely be packed with commentary on how Ms Markle will do a world of good for the ageing, bent-over, old-millennium House of Windsor, like Kate did but with bolts on. And it’s true, she will — in a short-term PR sense at least. She is beautiful, intelligent, had a career pre-royal life (and might even keep it), and — there’s no escaping this — she has a very different heritage to the slightly strange, soft-chinned, super-European inhabitants of our royal palaces. For a monarchy keen to prove it is dusting itself down and getting ‘with it’ — they probably really use the phrase ‘with it’, bless ’em — Ms Markle is just perfect.

Indeed, I predict she will be the first SJW princess. Or duchess. She’s so right-on it’s painful. She’s worked with UN Women, waxed lyrical about the HeForShe campaign, visited Rwanda to find out how they manage to have so many women in parliament — 64 percent! (Nobody ruin her fantasy by telling her what a nasty, authoritarian state Paul Kagame’s Rwanda is.) She will likely have the likes of Emma Watson and the trans correspondent from Buzzfeed over for tea at Kensington Palace, and my, how they will fawn.

If Kate refreshed the monarchy in the eyes of young girls who dream of being princesses and older people who miss Princess Diana (like my mum, who adores Kate), then Ms Markle is likely to achieve something even more spectacular: respect for royals among the identity-politics set. They’re probably making sassy gifs of her as we speak. One of her flicking back her hair to signal tough-girl disdain, another of her rolling her eyes at all you racist idiots. Yes, echoing Harry, whose press secretary last year snootily reprimanded the press for the ‘racial undertones’ in its coverage of Ms Markle, right-on observers are already policing Meghan-mania for signs of prejudice. Which they will find, because they find it everywhere, the tragic weirdos.

I know Diana fancied herself as the first SJW princess — all touchy, feely, therapeutic — but she was too posh to pull it off. Ms Markle, however, will be the perfect royal for the Twitter age, for this gifs-and-memes era, for a shallow identitarian culture that loves female celebs who talk about women’s suffering. The love will be kind-of ironic — everything is now — and annoying as hell, but yes, it will be good for the Windsors. Meghan will drag them into the 2010s.

But fear not, my republican friends. For the further the British monarchy goes down the celebrity route, the more it makes itself, or at least its historic mission, redundant. This institution now derives its authority almost entirely from celebrity and glamour rather than God or tradition. It has refashioned its rule as therapeutic rather than monarchical: witness William and Harry’s mental-health campaigning. The monarchy is searching for a new mission, a new source of legitimacy, and it is landing, time and again, on celebrity. ‘We’re famous and attractive — that’s enough, right?’

Yes, it is. For now. But it won’t last. This temporary cure for the Windsors’ ills might also prove to be the thing that kills their House. For if our royals are not that different to celebrities, and in fact have become celebrities, then why do we bow before them? Why do we pay them? Why do we have them as our head of state? Why do we have the Royal Prerogative, through which, in theory at least, the monarch can declare war? We wouldn’t let Kim Kardashian declare war. So, republicans, embrace the era of celebrity royalty, because it raises more questions about the monarchy than the establishment yet realises, or can possibly handle.