The proposed state visit by King Charles III on July 4 in the rose garden at the White House – to mark the 250th anniversary of the US Declaration of Independence- has taken on huge significance.
With Donald Trump in the process of imposing new tariffs over Greenland and renewing threats against other allies, there are few levers Sir Keir Starmer can pull to persuade the US president to be more reasonable.
But the royal visit this year is perhaps the only lever which can now be deployed to stop an international crisis from spiralling out of control.
If there is one card the UK holds in its dealings with Mr Trump, it is the royal family.
Partly because of his late mother coming from Scotland, President Trump reveres Britain’s royals and the trappings of power that go along with them.
It is already a well-established fact that the senior royals, in particular, are in essence an extension of the Foreign, Commonwealth and Development Office (FCDO) and this is most true regarding the careful dealings with America’s capricious 47th president.
Sir Keir has already deployed Prince William as a crucial go-between with the US president. The relationship began in late 2024 just before Trump’s inauguration when he and William met in Paris ahead of the reopening of Notre Dame cathedral.
Since then, the prince and president speak regularly, The Independent has been told – even more than Trump speaks to Starmer.
Most important though has been the pageantry. One of the ways that Sir Keir was able to outperform the EU on getting a trade deal post Trump tariffs was because of the Trump’s historic second state visit to the UK.
He may be regretting the appointment now, but the prospect of the state visit also ensured Trump did not reject Starmer’s first choice ambassador to the US – Lord Mandelson.
The state visit became a sort of golden carrot which the president fixated on and told those close to him that he did not want to go wrong in any way.
So Trump made it clear that he did not want anything to interfere with that and was willing to be much more amenable to the UK.
In the process, it gave space for Starmer to build his relationship with the US president and earn his status internationally as a “Trump whisperer.”
Going forward, the plan to send the King or perhaps Prince of Wales on a state visit for the 250th anniversary of the Declaration of Independence on 4 July is perhaps now even more important for Trump and what he sees as his legacy.
So as diplomatic tensions mount and the threat of tariffs increases, this visit and whether it goes ahead will be highly significant.
If the UK is in recession because of Trump tariffs and the Nato alliance has collapsed over the US president’s demands for Greenland, then it seems impossible for a senior royal to roll up and essentially give the US president their blessing.
But the threat it might not happen may even at this stage be enough to stay Trump’s hand.
There is a risk though. Trump is not a man who takes being slighted lying down. If ar oyal state visit is cancelled he will take it personally and things could get much worse.
And it is not as if brandishing royalty at Trump has helped hugely with international issues like Ukraine or the Middle East.
As ever, Sir Keir has a difficult tightrope to walk in the diplomatic turbulence of the Trump presidency.
