In the Trump Era, King Charles Has a New and Very Delicate Role to Play

King Charles III flew by helicopter to the H.M.S. Prince of Wales in the English Channel on Tuesday, where he mingled with sailors and watched as fighter jets took off from the deck of the ship, a Royal Navy aircraft carrier. It might have been a welcome getaway from his suddenly complicated social life.

In the span of five days, Charles had invited President Trump for a rare second state visit to Britain and then played host to two of Mr. Trump’s biggest antagonists, President Volodymyr Zelensky of Ukraine and Prime Minister Justin Trudeau of Canada, at his country estate northeast of London.

None of those gestures by Charles was overtly political. As is customary in Britain’s constitutional monarchy, he acted at the behest of the government. But they have nevertheless drawn the 76-year-old king into a swirling diplomatic drama in a way that is almost unheard-of for a British sovereign.

Charles’s invitation to Mr. Trump, delivered with much fanfare by Prime Minister Keir Starmer on Thursday in the Oval Office, has become more contentious since the president clashed with Mr. Zelensky over American support for Ukraine the day after his more harmonious session with Mr. Starmer.

“Now Stop the State Visit for ‘Bully’ Trump,” The Mail on Sunday, a right-wing tabloid, said on its front page. It cited a chorus of demands by lawmakers and other critics that the government rescind the invitation to Mr. Trump to telegraph Britain’s displeasure with the president and solidarity with Ukraine.

Symbolically, Charles may have done the next best thing: hosting Mr. Zelensky at his estate, Sandringham, after the president attended a summit meeting on Sunday devoted to Ukraine. Buckingham Palace did not disclose what they talked about but said Mr. Zelensky was “warmly received” by Charles, who served him tea in Sandringham’s Saloon room.