On Tuesday, towards the end of a trip limited to just 24 hours on Canadian soil, the King will appear at the country’s senate to officially open its parliament.

He will be there as King of Canada, head of state at a moment in history at which Canadian sovereignty is very publicly under threat. It will be, Canadian sources say, a test like no other.

Delivering a speech that will knit together the Canadian government’s priorities with some of his own words, all eyes will be on the King as he walks the unexpected diplomatic minefield of 2025.

In doing so, he will answer the question of the monarchy’s relevance in Canada for a new generation: a chance to prove how having a King who lives so far away still benefits the national interest.

The King will be following in the footsteps of his late mother Queen Elizabeth II, attending the state opening of parliament on his first visit to Canada as sovereign and delivering only the third royal speech from its throne.

This time though, it comes shortly after the country faced a threat of invasion from its nearest neighbour, which unified Canadians in outrage. Donald Trump, US president, suggested he would annex it to make it the 51st state.

Credit: Reuters

“Canada has a steadfast defender in our sovereign,” said Mark Carney, Canada’s prime minister, who has repeated that his country is “not for sale, ever”.

The King’s visit, said Canada’s high commissioner in the UK, will “reinforce the power and the strength” of that message.

“In a subtle way,” writes the Ottawa Citizen newspaper, “the King will be sending a message about Canada’s place in the world.”

The Globe and Mail, the national newspaper, predicts that it is a chance for the monarchy to find “new relevance as Trump threatens annexation”, saying it was an “opportune time for King Charles, who has struggled to win over the public”.

For Patricia Treble, a Canadian journalist who has been covering royal visits for more than 20 years, “everything from speeches to clothes and jewellery must scream ‘the King and Queen of Canada are defending Canada’s sovereignty’”.

“This is an existential threat to Canada,” she said of Mr Trump’s attitude to her country. “All Canadians understand the seriousness of this threat and importance of this visit.

“Everything must be done to show the King and Queen are coming to Canada, defending Canada’s sovereignty.

“People are going to be counting every word the King says. This is a turning point for the Crown – this trip really matters.”

Ms Treble added that the issue had underlined the point of having a monarchy to the public: “All of a sudden the advantages are very apparent.”

The royal visit, which the palace hopes will be a tour de force of soft-power diplomacy, will span just two days, with the 76-year-old King – still undergoing cancer treatment – fitting in eight engagements and a speech to the Canadian parliament.

He will drop the puck in a street hockey game, travel through the streets with the Queen in the 1902 State Landau, lay a wreath at the Second World War memorial in the year of the 80th anniversary of VJ Day, and watch a Royal Canadian Air Force flyover.

The King will also find himself “navigating diplomatic rapids”, palace sources concede, which will leave him drawing on a lifetime of international diplomacy and cross-country friendships.

The issue has been complicated by the Royal family’s involvement in the UK’s “soft-power” wooing of the US ahead of a trade deal earlier this year, with the King set to host Mr Trump in September before a second state visit next year.

Canadians were “not impressed” by the invitation, Mr Carney has said, leaving the prospect that the King would visit the US or host Mr Trump before he had set foot in Canada as its King.

He will now make it to Canada first.

The King and Queen’s trip to Canada was originally planned for spring 2024, never announced but postponed while the King was beginning his cancer treatment and delayed again for the Canadian election cycle.

The new invitation to open parliament was made at short notice, put in the diary for as soon as possible once Mr Carney’s Liberal Party was elected.

‘Held in high regard’

The trip schedule includes engagements allowing the King and Queen to meet members of the public, Canadian leaders, and for the Queen to be sworn in as a member of the King’s Privy Council for Canada.

“I think people will understand that there is a particular role as head of state of Canada,” said one palace source, on the differing demands of the King overseas.

“The King is held in high regard by global leaders across geographical and political boundaries.

“Hopefully he will be able to bring the wisdom, experience and personal relationships to bear, to smooth over any wrinkles without it being a provocation.”

The King has already been the recipient of “warm comments” from both Mr Trump and Mr Carney, they said, after in-person meetings with both this year.

There will be “really lovely symmetry” with Queen Elizabeth II’s first visit, added a palace source, with the King “very pleased and proud to be following in her footsteps”.

The two-day trip does not preclude a longer visit in the near future.

“The only sadness is that he’s not able to go for longer and further,” said the source close to the King. “There is a keen appetite if an invitation was issued to make a fuller visit.”

“This is a highly significant royal visit,” said Carolyn Harris, a royal historian based in Canada.

“The King acts on the advice of the Canadian government and has to remain above party politics, so he has to avoid using particular slogans. But the very fact of the presence of the King and Queen is a reminder of Canadian sovereignty.”

‘Gesture of solidarity’

Robert Bothwell, historian, said that the King’s speech in parliament “is a gesture of solidarity and identity that can be construed to be a gesture of support”.

The UK Government, watching from afar, will also be mindful of how the visit is seen by the rest of the Commonwealth, and within Mr Trump’s administration at a critical time for the “special relationship”.

Pete Hoekstra, the new US ambassador to Canada, said that using the King’s visit to send messages to his country is not necessary, urging politicians to “move on”.

“We’re thrilled that the King will be here,” he added. “If there’s a message in there, you know, there’s easier ways to send messages. Just give me a call. Carney can call the president at any time.”

The King, as Prince Charles, has previously visited Canada 19 times. Queen Elizabeth II read the speech at the state opening of parliament in 1957, and delivered a speech from the throne in 1977.

Daniel Béland, a political science professor at McGill University in Montreal, predicts that the King is “unlikely to comment directly on the 51st state issue”.

“Yet, his introductory remarks could feature broad statements about Canada’s integrity and sovereignty,” he added. “At least this is what many Canadians would like him to do.”