King Charles III's address to Congress was always going to involve walking a diplomatic tightrope.

But he managed to make a speech that made a number of important political points - all delivered in a gentle, Kingly way.

There were references to Nato and Ukraine, a reminder of the importance of Western democracy, and a subtle message about climate change - something US President Donald Trump has previously called a "hoax".

His words prompted no fewer than 12 standing ovations, suggesting his points landed with his audience.

And the reaction from across the world has been overwhelmingly positive too. The New York Times comments on his "subtle rebuttals" to Trump, while Le Monde said it took a King from the UK to remind US politicians of "the habit of sophisticated speeches".

Royal meaning must often be decoded, and the King will have wanted to avoid offending his host. Notwithstanding, this was a monarch standing his ground on the issues that matter the most to him.

So how did the King navigate the delicate balance of making a point while staying cordial?

The King's speech defended Nato, at a time when Trump has been openly criticising members of the military alliance for their reluctance to play a greater role in the war in Iran.

Citing former US Secretary of State Henry Kissinger, the monarch spoke of an Atlantic "partnership", which he said was "based on twin pillars: Europe and America".

He also referred to the events following the attacks of September 11, 2001, when Nato allies mobilised in defence of the US.

"In the immediate aftermath of 9/11, when Nato invoked Article Five for the first time, and the United Nations Security Council was united in the face of terror, we answered the call together," he said.

Here, the King's message was both robust and at the same time, a subtle reminder to the US president of the merits of the alliance.

Last month, Trump said he had always considered the 32-member Nato defence alliance to be a "one-way street", writing: "We will protect them, but they will do nothing for us."

The King later reiterated his support of Nato during his toast at the state dinner. It's clearly a message Downing Street will hope sticks in the president's head.

Trump has in the past criticised British naval capacity, calling its ships "toys" and saying UK aircraft carriers "didn't work".

This viewpoint, too, was carefully challenged by the King, who said he himself had served with "immense pride" in the Royal Navy, following in "the naval footsteps" of his father, the late Duke of Edinburgh.

The comments about the Navy could be seen as a way to emphasise the importance of strong relations between the two nations - with the King reflecting on the importance of security and defence ties, and shared intelligence.

And there was also a nod to the Navy in the choice of gift - with Charles presenting the president with a bell from his WW2 submarine namesake, HMS Trump.

When it came to reminding the US of the checks and balances in government, the King chose his words carefully.

The president's critics have frequently attacked him for his efforts to expand executive White House power.

The King didn't directly criticise the Trump administration. But he gently made his position clear.

Turning to English history, he invoked the Magna Carta and noted it had been cited in more than 160 US Supreme Court cases since 1789, "not least as the foundation of the principle that executive power is subject to checks and balances".

The remarks drew a standing ovation, starting on the Democratic side of the chamber, before spreading across the entire room.

Trump has called climate change a "hoax" and a "con job", and pulled out of the Paris agreement on climate change.

In the face of that, the nature-loving King made his thoughts about the environment known.

Towards the end of his speech, he reflected on "the natural wonders" of the US and talked of a shared responsibility to protect "our most precious and irreplaceable asset".

And then came a more direct warning about the risks if we don't.

"We ignore at our peril the fact that these natural systems, in other words, nature's own economy, provide the foundation for our prosperity and our national security," he said.

The King had come under pressure to meet survivors of the late sex offender Jeffrey Epstein during the state visit to the US - not least given the scandal surrounding his brother Andrew Mountbatten-Windsor.

That was not possible, according to Palace sources, who argue it could jeopardise legal proceedings and stop justice for victims.

There was no mention of Epstein in the speech.

But at the end, a veiled reference to the need to "support victims of some of the ills that, so tragically, exist in both our societies today".

It may not be enough for those who wanted the royal visitors to do more on this trip, including US Congressman Ro Khanna, Epstein survivor Lisa Phillips and the family of the late Virginia Giuffre.

Ahead of the trip, Palace sources said the King could play a unique role in supporting a UK and US partnership that had "survived many presidencies and of course many reigns".

And there were plenty of references to the importance of the relationship throughout the speech, as well as a nod from the King about his support for UK Prime Minister Sir Keir Starmer - who has faced numerous jibes from Trump in recent weeks over his stance on the war in Iran.

"As my prime minister said last month, ours is an indispensable partnership. We must not disregard everything that has sustained us for the last 80 years. Instead, we must build on it," the King said.

Not all of the King's speech needed inferring.

When it came to defending Ukraine, the King was pointed.

He said the strength of the US-UK partnership has been used to take on common adversaries and to secure the world.

Now, he said, it's needed to safeguard Ukraine in the midst of war from Russia.

"Today, Mr Speaker, that same, unyielding resolve is needed for the defence of Ukraine and her most courageous people - in order to secure a truly just and lasting peace," he said.

Here, the message to Trump seemed clear. The US president has at times curried favour with Moscow, casting doubt on America's long-term commitment to European security.

"The challenges we face are too great for any one nation to bear alone," noted the King, as he placed Ukraine within a wider set of global crises and urged co-operation between allies.

The state visit has come at a difficult time for the Royal Family, which remains under scrutiny over Mountbatten-Windsor's friendship with Epstein. Those negative headlines are likely to persist.

But in this speech, the King navigated tricky diplomatic waters and managed to gently reject a number of Trump's claims - all while keeping a smile on the president's face. That is no mean feat.