Over the last two months, US President Donald Trump has repeatedly slammed UK Prime Minister Keir Starmer over his reluctance to help the US in the Iran war. When the UK initially refused to let the US use its military bases to launch airstrikes at the beginning of March, Trump quipped, “This is no [Winston] Churchill we’re dealing with here.” He also needled Starmer this month over his appointment of Peter Mandelson as London’s ambassador to Washington – the decision has been a source of severe political pain for the PM domestically due to Mandelson’s links to child sex offender Jeffrey Epstein. The US is now reportedly weighing whether to maintain its support for the UK’s de facto sovereignty over the Falkland Islands, a territory off the coast of Argentina.
It is perhaps eerie that Charles’ trip comes as the US gets ready to celebrate the 250th anniversary of declaring its independence from Great Britain.
Yet the US’s relationships with many of its allies are under strain. Europe is preparing for a future in which the US no longer acts as its safety net. Japan, too, has been inching away from the pacifist stance it has upheld since World War II, as questions mount over whether the US would get involved in a China-Taiwan war. Closer to home, the US’s two neighbors Canada and Mexico are grappling with Trump’s confrontational stance and what it might mean for the USMCA agreement that accounts for close to $2 trillion in annual trade.
But can the King help the UK overcome this overwhelming trend?
Charles is somewhat insulated from the day-to-day politics that often dictate a political leader’s decisions – after all, the King isn’t elected. As such, he’s better positioned to focus on the UK’s long-term interests, which likely include retaining a strong relationship with the most powerful country in the world. Other NATO leaders, by contrast, may try to harness their voters’ distrust of Trump for political gain, much as Canada’s Mark Carney and Spain’s Pedro Sánchez have done.
What’s more, Trump is a longtime admirer of the UK monarchy. He openly voiced his wonder at coming to Windsor Castle during his first state visit in 2018, back when Queen Elizabeth II was at the helm. Indeed, different regal estates have inspired some of the designs at his Mar-a-Lago estate. That affinity appears to have stemmed from Trump’s Scottish mother, herself a loyal supporter of the royal family.
“I think he has reverence, probably, for monarchs writ large,” Liz Mair, a Republican political strategist who holds UK citizenship, told GZERO. “But the King [of England] would rank foremost among those.”
Since Charles took the throne, the US leader has been nothing but effusive about the King – a theme that continued while the pair shared tea at the White House yesterday.
The UK prime minister has sought to capitalize on the goodwill. Barely a month into Trump’s second term, Starmer – whose own premiership was still nascent – came to the White House and presented his American counterpart with a letter. It was an invitation from Charles for a second state visit, something not usually afforded to US presidents in their second term.
“It’ll be an honor to be there,” said Trump, who appeared humbled. That visit took place last year.
Until the Iran war, the outreach appeared to be paying dividends. The UK was the first to sign a trade pact with Washington following Trump’s “Liberation Day” tariffs of April 2, 2025. Until recently, Trump had repeatedly praised Starmer, even though the two leaders sit on opposite sides of the political spectrum. That reverence appeared to trickle down the proverbial food chain, with Vice President JD Vance forming a close relationship with Justice Secretary David Lammy.
However, there is a ceiling on what Charles can deliver, according to Mair. The royal family has asserted soft power for some time, including on trade, but it lacks the capacity to influence the US’s position on its foreign policy stances.
“I don’t really think he’s in a position to do much in the way of hard diplomacy,” said Mair, before referencing the Iran war. The King could be helpful, though, in forestalling future US tariffs on the UK.
Every rose has its thorns. The scandal surrounding Jeffrey Epstein has posed problems for both the US and the UK, affecting Charles, Trump, and Starmer alike. The US president has faced scrutiny over his past links to Epstein, while Charles’ brother Andrew Mountbatten-Windsor was forced by the King to relinquish his royal titles over his relationship with the disgraced financier. Meanwhile Starmer’s premiership is in jeopardy over his decision to appoint Mandelson, who appeared to have a close relationship with Epstein.
Charles has chosen not to visit Epstein survivors during his trip.
Now, the scandal is presenting a challenge for US-UK relations. The Financial Times reported this morning that the current UK Ambassador to the US Christian Turner, Mandelson’s successor, criticized Washington’s political system for its failure to hold to account those who had links to the disgraced financier. Turner made the comments at an event in Washington in mid-February. He also suggested that the only “special relationship” that the US has is “probably” with Israel.
There’s potential for further strains between Westminster and Washington. With Starmer in a political pickle, it may be increasingly tempting him to use the US leader as a foil as a way to boost his standing at home, much as Italy’s Giorgia Meloni has done in recent weeks. If that happens, it will be up to the King – and the King alone – to maintain what’s left of the so-called “special relationship.”
