London (CNN) - Diplomacy was dealt a hammer blow this week.
Kim Darroch's sudden departure from Washington will have many diplomats wondering if they could be next.
The UK ambassador's resignation -- after his assessment of Donald Trump was leaked -- has created a global chill that will undoubtedly be felt for some while, and not just by British diplomats. It's no secret that many foreign ambassadors have sent home scathing assessments of the President.
"The leaker is guilty of the worst breach of trust in our service in my career. The damage after three days is evident in the resignation of the most senior British diplomat," said Simon McDonald, head of Britain's Diplomatic Service.
So what should diplomats do? Stay shtum when your capital asks for your unvarnished assessment of person A, or situation B? In so doing, you would fail your central mission of ensuring your country has every advantage.
Or would you tone down your assessment, risk under-informing your political bosses, and by extension undermine your national interest ?
Theresa May wants a third way: Keep up the frank exchanges but find new ways to avoid leaks.
Following his resignation, she praised Darroch and told UK lawmakers: "Good government depends on public servants being able to give full and frank advice. I want all our public servants to have the confidence to be able to do that."
To restore that confidence might require a shakeup in the way diplomats report. Currently "diptels" -- the cables which Darroch used to tell May that Trump and his White House were "inept" and "dysfunctional" -- get security gradings based on "national security" rather than political sensitivity.
To counter leaks, a new, more restrictive grading could take into account the political impact a leaked diptel might have, which would mean fewer people would see the ambassador's raw assessments.
But in a new era of British politics riven by toxic disputes over Brexit, even limiting the reach of diptels may not be enough. If political infighting continues to hobble the British government as it does now, diplomats could become hostage to populist sentiment at home.
It is a challenge Britain's incoming Prime Minister will inherit when he picks up the reigns of leadership on July 24. One government official told CNN that Darroch quit in part because he didn't have the backing of the frontrunner in the race for Prime Minister, former Foreign Secretary Boris Johnson.
Johnson has been fighting back, calling Darroch "superb" and lambasting the leaker: "I think that whoever leaked his diptels really has done a grave disservice to our civil servants, to people who give impartial advice, to ministers and I hope that whoever it is rundown caught and eviscerated."
But Johnson may find perceptions hard to shift: He and Darroch differed on Trump and Brexit. Johnson is a fan of Trump and hard Brexit; Darroch is anti-Trump and pro-EU.
The UK's main opposition party Labour is adding to the politicization calling Johnson a "patsy" of Trump and a "lick-spittle." (Johnson's leadership rival, Jeremy Hunt, was swift to back Darroch, in part publicly forcing Johnson's hand on the issue, highlighting the deeply politicized state of British politics.)
None of this is conducive to liberating diplomats to do their job and speak their minds freely without fear some politically motivated leaker won't expose them.
On this, Johnson is speaking a good game. "It is not right that civil servants careers' prospects should be dragged into the political agenda," he has said. But whether or not Johnson can rebuild trust is an open question.
Former Conservative PM John Major said Johnson would do well to show that "loyalty is a two-way street" in his handling of the civil service, after his failure to back Darroch publicly, when he needed it the most.
Johnson's critics would argue he often fails to deliver on his lofty rhetoric, yet now his own leadership and relations with foreign leaders may rise and fall on his curbing the infighting many accuse him of manipulating.
The awful lesson of the leaks that brought down Darroch is that every diplomat, no matter how far from their capital they serve, is ultimately only as secure as politics back home are stable. In an era of growing populism, and increasing global tensions, it won't be just British diplomats who are looking over their shoulders.