By Stephen Fidler
LONDON -- The resignation this week of Britain's ambassador to Washington under duress has set off a period of self-examination in the U.K. as the nation struggles to find its place in the world ahead of its planned European Union exit.
Mr. Trump said he would refuse to work with the envoy, Kim Darroch, calling him "very stupid" and "wacky" in Twitter messages following the leaking of secret diplomatic cables in which Mr. Darroch described what he called chronic dysfunction in the Trump administration. The ambassador's departure is occurring at a moment of strategic loneliness for Britain.
"It's an irony of Brexit that just as we are divorcing from our partners in the EU, we find a less committed relationship transatlantically," said John Sawers, a former head of MI6 who now runs his own Newbridge Advisory consulting firm.
The U.K. is deeply divided internally over Brexit. Meanwhile, the global system of rules administered by international institutions on which medium-size powers like Britain could once depend is eroding. The U.K.'s vulnerability is emphasized by Mr. Trump's ambivalence about the North Atlantic Treaty Organization, the pillar of Britain's defense strategy.
"The international system is under great strain as we return to an era of great-power politics that is accentuated by the Trump approach," Mr. Sawers said. The Trump administration is comfortable with a world "where might is right and where power prevails."
The U.S. has been the senior partner in the "special relationship" since 1946 when Winston Churchill coined the phrase. Yet the two nations' ties have real depth across culture, commerce and government.
"The special relationship is more than just the White House and the prime minister," said Tom Tugendhat, chairman of the House of Commons foreign affairs committee.
Britain, with its capable intelligence services and niche military capabilities such as special forces, also is probably America's closest security partner. The U.K.'s role in helping to seize an Iranian tanker last week off the British territory of Gibraltar -- justified legally by the U.K. because it was bound for Syria in breach of EU sanctions -- supported Washington's aim of squeezing Tehran.
The move also brought risk for London -- a British warship trained its guns on three Iranian vessels that the U.K. said were blocking a British-flagged tanker in the Gulf on Thursday -- but not much evident reward. Days later, Mr. Trump didn't hold back from belittling Prime Minister Theresa May and insulting Mr. Darroch.
Mr. Trump's actions have already aroused sensitivities to accusations of being "America's poodle," never far below the surface in the U.K. Boris Johnson, Britain's next likely prime minister, was accused of just that when he refused to back Mr. Darroch or criticize Mr. Trump over his Twitter slap-down.
"If sovereignty doesn't allow us to choose our own representative, what is it but servitude?" Mr. Tugendhat asked in Parliament Thursday.
These worries are likely to increase after Brexit. A trade deal with Washington is regarded as a great prize in the pro-Brexit camp as a way of offsetting the reduced access to the EU market. But it would almost certainly require the U.K. to swallow American rules governing farm standards. And it isn't certain to be achieved.
"I don't see a trade deal with the U.K. that's easily accomplished," House Ways and Means Committee Chairman Richard Neal (D., Mass.) said on Wednesday. Any new U.S.-U.K. trade deal would pass through his panel. "I think that there's a naiveté on their part if they think that you break out of Brexit with no deal and then you embrace a bilateral with the United States? I don't see that happening."
The external challenge has been accompanied by a blow to the self-confidence of Britain's establishment, which has had a strong reputation internationally for effectiveness and relative lack of corruption.
Mr. Darroch's resignation shook the Foreign Office, the department's senior civil servant said Wednesday. On Thursday, Conservative lawmaker Roger Gale asked what the government would do to rebuild "shattered confidence of our diplomatic corps."
Unlike in the U.S., where political appointees occupy multiple levels of government and up to a half of ambassadorial posts, the U.K.'s traditionally impartial public servants reach into a higher level of administration. The U.K. currently has only one ambassador who is a political appointee -- the ambassador to Paris Edward Llewellyn -- and has never had more than three at any one time.
At its best, the system guarantees continuity and expertise as governments and ministers change. But senior civil servants and diplomats like Mr. Darroch have been depicted by pro-Brexit campaigners as a cabal in the heart of government trying to thwart Britain's exit from the EU.
That has brought them unprecedented and unwelcome political criticism that they have faced along with judiciary and other independent institutions such as the Bank of England.
Speaking to Parliament Thursday, Foreign Office Minister Alan Duncan spoke of a decay of British institutions and standards of behavior in public life. "Many of the codes of conduct I think are in free fall and it's leading to unacceptable attacks on judges, members of Parliament and broadcasters," he said.
Behind this is, depending on one's point of view, either the unappetizing realities of Brexit or the failure to deliver it more than three years after the 2016 referendum decision to leave the EU.
Mr. Sawers, reflecting the views of British officials and politicians past and present, said he believes the country will overcome its current challenges, just as it overcame the challenges of the 1970s when the country, beset by labor disputes and high inflation, appeared almost ungovernable.
The challenge will be that Brexit isn't going away soon. Assuming the U.K. leaves, whether it is with a negotiated deal or not, Britain will need to settle its future relationship with the bloc before it can define its status with the rest of the world.
If Britain doesn't leave, the economic fallout may be mitigated, but the internal political divisions that Brexit has exposed will likely linger.
--Siobhan Hughes in Washington contributed to this article.
Write to Stephen Fidler at firstname.lastname@example.org