British Ambassador Kim Darroch talks with guests at a reception to celebrate the royal wedding at the British ambassador's residence in Washington last year. (Erin Schaff for The Washington Post)

After a newspaper published accounts of the British ambassador to the United States describing President Trump as “inept” and “insecure” in private cables to London, the future of Kim Darroch’s assignment in Washington immediately appeared to be in doubt.

On Wednesday, Darroch resigned after days of intense criticism from opponents at home and pointed barbs from Trump himself, who called the ambassador “wacky," “a very stupid guy” and "a pompous fool.”

“We will no longer deal with him,” the president wrote in a tweet.

But were Darroch’s critical remarks about Trump so unusual? Well, no. There’s a long and not-so-secret history of diplomats in a foreign country trashing their hosts in private.

“His comments are entirely unsurprising from a historical perspective,” Calder Walton, a British lawyer and a fellow at Harvard University, wrote in an email. “Ambassadors rely on being able to give frank (often undiplomatic) opinions about their resident countries.”

In many instances, sending these unfavorable messages back home is one of the most important aspects of the job.

Extreme examples of this were messages from the foreign ambassadors stationed in Berlin during the reign of Adolf Hitler. Though the rise of the Nazi leader was often met with carefully considered language in public, in private, ambassadors would offer scathing assessments of the man.

André François-Poncet, the French ambassador to Germany, repeatedly offered warnings to Paris throughout his time in Berlin, from 1931 to 1938. At first, he was dismissive, writing in 1933 that “if intelligence consists essentially of a critical spirit, then Hitler is not intelligent."

Only a couple of years later, François-Poncet made a harsher assessment, describing Hitler in 1935 as a man of “brutal arrogance, violent, devoured by the madness of greatness … obstinate, stubborn and mean to the point of madness.”

American accounts were hardly much kinder. As the Nazis took power in 1933, George S. Messersmith, then the head of the U.S. Consulate in Germany, wrote to Washington, “some of them are psychopathic cases and would ordinarily be receiving treatment somewhere.”

Even Nevile Henderson, the British ambassador to Germany in the days before World War II who came to symbolize London’s “appeasement” policy, sent home critical notes about Hitler’s mental health and megalomania.

“He may have crossed the borderline into insanity,” he wrote after seeing the German leader speak in 1938.

Hitler was an unusual, and uniquely alarming, historical case. But these unvarnished views of world leaders by ambassadors are not rare, and the assessments are designed to help craft foreign policy.

A famous diplomatic cable sent by U.S. Ambassador George Kennan from Moscow in 1946 — later dubbed the Long Telegram — included thoughts on the mentality of Soviet leader Joseph Stalin.

“There is good reason to suspect that this Government is actually a conspiracy within a conspiracy,” he wrote. “I for one am reluctant to believe that Stalin himself receives anything like an objective picture of the outside world.”

What is unusual about Darroch’s remarks about Trump is not that he made them. It’s that they leaked. In general, ambassadors’ real views of their host countries are never published while they are in the country. They are only later released to the public, generally by scholars rather than journalists. (Most of the above examples are from historian Abraham Ascher.)

Leaks are unusual and can be embarrassing. In 2010, the release of tens of thousands of U.S. diplomatic cables by WikiLeaks provided unflattering American assessments of a variety of world leaders.

For U.S. rivals and foes, the criticism was pointed. A U.S. diplomat in Moscow had said that then-Russian President Dmitry Medvedev “plays Robin to Putin’s Batman,” referring to Russia’s then-prime minister, Vladimir Putin.

Another cable, written by the U.S. ambassador to Eritrea, Ronald McMullen, described President Isaias Afwerki as an “unhinged dictator” who “remains cruel and defiant.”

But often the worst criticism was reserved for allies. American diplomats dubbed Nicolas Sarkozy, then the president of France, as “thin-skinned” and an “emperor with no clothes.” Italy’s Silvio Berlusconi was “‘feckless, vain and ineffective,” while Britain’s Gordon Brown was described as an “abysmal” prime minister who lurched from “disaster to disaster.”

The leaks were a sensation throughout the world. In most cases, official reactions were measured, but some countries lodged complaints. Heather M. Hodges, the U.S. ambassador to Ecuador, was expelled for critical comments she had made in the leaked cables.

Darroch’s views are not unusual among the diplomatic corps in Washington. As he stepped down from his position this year, French Ambassador Gérard Araud gave a series of candid interviews in which he spoke at length about the Trump administration and its “whimsical, unpredictable, uninformed” leader.

And even among strong allies during what many considered to be a period in which relations were at peak strength, diplomacy is a balancing act that’s more complicated than it appears on the surface.

When former British ambassador to the United States Nicholas Henderson was asked about what he’d learned during his tenure in Washington years later, he replied: “If I reported to you what Mrs. Thatcher really thought about President Reagan, it would damage Anglo-American relations."