Addressing the United States Congress this week, King Charles III made a cameo appearance in his role as Australia's monarch: “We have agreed (to) the most ambitious submarine program in history – AUKUS – in partnership with Australia, a country of which I am also immensely proud to serve as Sovereign.”
The idea that a British monarch would switch crowns mid-speech and tout a key Australian strategic objective while on a state visit to the United States would have seemed far-fetched only two years ago when Joe Biden was president. But since Donald Trump took office a second time, Charles’ role as sovereign has taken on newfound utility for Commonwealth realms that are also traditional allies of the United States.
Canada was the first beneficiary of Charles’ diplomatic power with Trump. The US President began his second term in January 2025 threatening Canada with annexation, referring repeatedly to the country as America’s “51st state” and then prime minister Justin Trudeau as “governor”. All this was followed by Trump imposing tariffs on many Canadian goods.
In response, on 3 March 2025, Trudeau sought and received an audience with Charles at Sandringham House. Following the meeting, Trudeau released a statement stating that the two had discussed “matters of importance to Canadians – including, above all, Canada’s sovereign and independent future”. A day later, Charles was photographed wearing Canadian medals on his military uniform while inspecting the aircraft carrier HMS Prince of Wales before a deployment to the Indo-Pacific. The symbolism was hard to miss.
Charles’ public interventions boosted popular support for the monarchy in Canada. Two days before he opened the Canadian parliament on 27 May 2025 – a rarity for Canada’s sovereign – a poll found that 45% of Canadians said Canada should remain a constitutional monarchy, while 39% said they thought Canada should end its connection to the crown (15% said they did not know).
Though comparing opinion polls is a fraught business, Australian support for retaining a constitutional monarchy appears broadly in line with that in Canada. In November 2025, a poll found that 43% of Australians would support becoming a republic, while only 28% would rather Australia remain a monarchy (29% were undecided).
Given the relatively soft support for a republic and the well-documented difficulties of achieving constitutional change in Australia, including the failure of the Voice referendum in October 2023, the monarchy is likely to remain at the cornerstone of Australia’s constitution in the near-to-medium term at least.
Buckingham Palace will gladly open its doors whenever an Australian prime minister rings the bell.
The same can be said for Great Britain and Northern Ireland, whose “United Kingdom” Charles reigns over from Buckingham Palace. Writing for The Interpreter, Hans van Leeuwen argued that former prince Andrew’s relationship with disgraced financier Jeffrey Epstein had pushed the monarchy into “existential crisis”, raising questions about the longevity of the monarchy in its current form. But the monarchy is a resilient institution that has adapted throughout the centuries.
Charles’ state visit to the United States is yet another adaptation – this time for the Trumpian era, where his role as sovereign is seen as crucial to the advancement of British interests. His speeches to Congress and at a state banquet hosted by Trump would have been carefully drafted by Buckingham Palace in close coordination with British ambassador to Washington Christian Turner, Foreign Secretary Yvette Cooper and Prime Minister Keir Starmer.
But, when Charles gave the President of the United States a bell from HMS Trump – a vessel launched from a British shipyard in 1944 and attached to the Fourth Submarine Squadron in Australia during the Second World War – at a state banquet on 28 April, there came indication that another senior official may have been consulted on the King’s speech: Australian Prime Minister Anthony Albanese.
Though a genuine trilateral endeavour between Australia, the United Kingdom and the United States to create a new class of nuclear-powered submarine, the AUKUS submarine program benefits Australia most of the three partners, as it provides access to nuclear propulsion technology that Britain and America had long shared only between themselves.
That is why when Trump came to office a second time, professing an “America first” foreign policy that sidelined traditional alliances, securing the president’s endorsement for AUKUS was widely regarded as Albanese’s top priority during his official visit to the United States in October 2025 (an objective he achieved). That Charles lent his own support for AUKUS during a state visit to the United States shows that Buckingham Palace will gladly open its doors whenever an Australian prime minister rings the bell.
