Donald Trump is reshaping the world, one cavalier tweet at a time.

On Monday night, the president-elect took to Twitter to declare that “many people would like to see Nigel Farage represent Great Britain as their Ambassador to the United States. He would do a great job!”

Many people would like to see @Nigel_Farage represent Great Britain as their Ambassador to the United States. He would do a great job! — Donald J. Trump (@realDonaldTrump) November 22, 2016

Trump, who often uses the vague “many people” formulation to give his own opinions more weight, was putting a good word in for his friend Farage, the iconic Brexit advocate and interim leader of the Britain’s anti-immigrant UK Independence Party. Farage campaigned in the US on Trump’s behalf and was the first UK politician to meet with the president-elect after his victory.

The British prime minister’s office swiftly swatted the idea down, saying the position was already filled by a capable diplomat and that the matter was something for the UK to handle on its own. The job is currently held by Sir Kim Darroch, who took up the post in January. Traditionally, it lasts four years or longer.

On Tuesday, Trump’s remarks served as a source of laughter in the House of Commons, the lower chamber of Parliament in the UK.

Conservative Member of Parliament Simon Burns quipped that perhaps the UK should recommend Hillary Clinton as its desired ambassador to Britain, a joke referring to the fact that Farage is outside the governing Conservative Party.

Amid raucous laughter, British Foreign Secretary Boris Johnson then declared that the current ambassador was doing a fine job. “We have a first-rate ambassador in Washington doing a very good job of relating both with the present administration and the administration-to-be, and there is no vacancy for that position,” he said before Parliament.

.@BorisJohnson says there is "no vacancy" for ambassador to US after Donald Trump backed Nigel Farage https://t.co/VjQMrci0ZF — Sky News (@SkyNews) November 22, 2016

As you can gather from the reactions, Trump’s unsolicited recommendation for an ambassador to the US is not the sort of things presidents usually do.

“It’s unheard of, as far as I know — I can’t recall this ever happening before,” Jordan Tama, a professor of international relations at American University in Washington, DC, told me. “The only case in which presidents have changed foreign diplomatic personnel stationed in their country is when the US was convinced that foreign diplomats were acting as spies.”

Trump’s tweet was the latest example of how his shoot-from-the-hip style of conduct isn’t something that’s going to fade away as he transitions from the campaign trail to the White House. But it’s important to realize that his faux pas is bigger than just departing from established diplomatic norms. Trump didn’t just breach etiquette — he revealed a total lack of comprehension of how diplomacy works.

What Trump just did is basically unprecedented

Telling a foreign country whom they should pick as an ambassador betrays a fundamental lack of understanding of what ambassadors do. British ambassadors are hired to advance British interests. They’re expected to help communicate what Britain wants and needs from its relationship with other countries. That could mean negotiating with the US over how much the UK is willing to commit its military to American-led wars, or discussing the terms of a future free-trade agreement.

The US and the UK are extremely close allies, so those conversations are relatively amicable. Yet they still involve tough talks about divergent interests and resource commitment. For example, the UK will dedicate troops to American military interventions out of obligation to their partnership, but they’re also going to balance that against public opinion of that war at home.

Navigating these kinds of tricky diplomatic situations requires an ambassador who is able to strongly assert Britain's interests with finesse. Telling the British how to choose that person isn’t just inappropriate, it reflects a failure to understand how the game works.

To make it even worse, Trump’s recommendation is for someone who leads a tiny and polarizing party outside of current British leadership. Consider how Farage, who was completely shocked by Trump’s tweet, described his relationship with the Conservative Party to CNN:

"The British Conservative Party are incredibly snobby about me. They've always looked down upon me. They find it very difficult to even have a conversation with me," he said. "If they came to me and said, 'Would you want to do something that would help the benefit of our country, and our trade relationship with America, and that would work both ways,' if they came and asked me to do it, of course I'd think very hard about doing it. But I honestly think it's unlikely.”

Trump wants the British government’s chief emissary to Washington to be somebody who isn’t even respected by the party in power. Imagine how that comes across to the British. Actually, you don’t have to imagine it. Christopher Meyer, a former British ambassador to the US, summed it up in an interview with the BBC:

“It would be barking mad to suddenly sack him and replace [the current ambassador] with a politician who a) knows nothing about diplomacy and foreign relations, b) is not even a political friend of Theresa May, and c) is hopelessly compromised by his association and apparent friendship with Donald Trump. That would be lunacy walking on stilts.”

Even more remarkable (though not particularly surprising) is that Trump did this over Twitter — and not, say, on a private phone call that ended up being leaked to the press.

There is method to Trump’s madness

As clueless as Trump’s un-diplomatic tweet was, it would be wrong to conclude that the sentiment behind it was entirely thoughtless.

Trump and Farage are figureheads of political movements that bear significant resemblance to each other. Both Trump’s wing of the GOP and Farage’s UKIP are populist, hostile to immigrants, and averse to multiculturalism. Both Trump and Farage have shocked the world by pioneering a new wave of skepticism of free trade in the Anglo-American world. Trump was deliberately putting the spotlight on someone who sees the world through similar eyes.

And he was also trying to boost a friend. Trump has shown a pattern of trying to reward loyalists and early supporters, and Farage rallied on his behalf on the campaign trail. Trump seems to want to pick people for jobs based in part on how much affection they’ve shown for him.

So far, Trump has been gearing up for the presidency based on his instincts as a businessman and a tendency to reward those whom he feels close to. It grows more evident by the day that he has little understanding of what he’s gotten himself into.