In October 2020, just over a year after he was elected president of Ukraine, Volodymyr Zelensky and his wife, Olena Zelenska, took an official trip to Britain that included a visit to Buckingham Palace to meet with Prince William and his wife Catherine, now Princess of Wales. At the time, the Ukrainian President, like the Prince, wore the uniform of a peace time leader: a dark suit and tie and black shoes polished to a pristine glow.

Two and a half years later, things looked very different.

On Feb. 8, just before the anniversary of the war in Ukraine, Mr. Zelensky returned: meeting with Prime Minister Rishi Sunak, addressing Parliament and traveling to Buckingham Palace to meet with King Charles III — this time in what he has made the symbol of his status as wartime leader: a military green sweatshirt with the Ukrainian trident at the throat, military cargo pants and Lowa task force boots.

Yup, he didn’t abandon his sweatshirt, even for the King (who was in his usual Savile Row blue suit and tie). The image tells the story more than words can.

This de facto uniform, which Mr. Zelensky has worn unrelentingly since the war began no matter what the context — in the soaring arches of Westminster Hall, the gilded rooms of the Palace, the oaken arena of Congress, the grand backdrop of the White House and which he will almost certainly wear later in the week when he travels to Brussels to meet with European Union leaders — places the reality of the war front and central in any picture, any conversation. It puts the war above traditional protocol and propriety, and makes it impossible to gloss over the reality of its continued trauma and even ugliness.

It interrupts the usual course of diplomatic events and expectations. It’s jarring among the sea of blue suits. It sets him apart. That is the point.

It’s a reminder, as Mr. Zelensky said to Parliament, that “the battle continues.” That even as he speaks to the King of Britain, who was trained as an air force pilot, his people continue to fight, and that “in Ukraine today every air force pilot is a king.” It’s a demonstration of solidarity with those back at home; an acknowledgment of the people Mr. Zelensky represents.

And it’s a language everyone watching can understand, in the blink of an eye: King, MP, random person scrolling through Instagram. The military drab clothes of the foot soldier are an almost universal vernacular. Since the beginning of this war, Mr. Zelensky has understood that in this visual age the “theater of operations” has multiple meanings.

That’s why what he wears matters — and the fact he continues to wear the same thing matters. It’s a strategic tool; an integral part of the battle for global support and his message to the world. And it has set its own precedent.

As John McFall, the Speaker of the House of Lords said, “In testing times leaders must be visible.” Mr. Zelensky has proved a master at using the tools of visibility. He has made them weapons, of their own kind.