The U.S. ambassador to Estonia - a NATO ally on the edge of Russia - abruptly resigned Friday, telling friends that he cannot abide President Donald Trump's apparent hostility toward institutions that have stabilized Europe since the end of the Cold War.
James Melville's decision to abandon the embassy comes at a crucial moment for independent countries along Russia's western border - amid the possibility of military conflicts and as Trump suggests he is rethinking America's traditional support for its allies in Moscow's shadow.
"The honorable course is to resign," Melville wrote on Facebook. "Having served under six presidents and 11 secretaries of state, I never really thought it would reach that point for me."
He added: "For the President to say the [European Union] was 'set up to take advantage of the United States, to attack our piggy bank,' or that 'NATO is as bad as NAFTA' is not only factually wrong, but proves to me that it's time to go."
Estonia is one of several formerly Soviet-controlled countries that has since joined the North Atlantic Treaty Organization - essentially allying with the United States and western Europe, whose militaries protect Estonia against Russian aggression.
Situated between Russia and the Baltic sea, tiny Estonia has been especially wary of its former occupier since 2007, when a massive cyber attack from Russian servers crippled Estonia's government, banks, and news organizations, according to the BBC.
Since then, Russia has sent military forces into others neighbors - Georgia and Ukraine - raising fears that it could one day target the Baltic states.
Just before the U.S. presidential election in 2016, The Washington Post documented how NATO fighter jets routinely scrambled from an Estonian air base to meet Russian warplanes that buzzed the country's airspace. Both Russia and NATO have recently staged military exercises that some analysts see as thinly disguised simulations of a war over the Baltic region.
As for the leaders of two most powerful countries in this conflict: Russian President Vladimir Putin sounds increasingly hawkish toward what many Russians see as an aggressive, expansionist military bloc on his western border - and Trump sounds increasingly amenable to the Kremlin's point of view.
A few months into Trump's presidency, The Post asked Estonian President Kersti Kaljulaid if she was worried about a Russian military attack.
"Actually, no," she replied. "Because of NATO."
But, Kaljulaid added, "I am afraid now that the resolve of the Western countries may not hold in the case of Ukraine."
Trump has given her plenty more to worry about since that interview.
As special counsel Robert Mueller looks into possible coordination between his presidential campaign and Moscow, Trump has suggested that the United States may recognize Russia's 2014 annexation of a Ukrainian peninsula. He has appeared to undermine the European Union, to which Estonia belongs. He has accused other members of not spending enough on NATO, and - according to Axios - disparaged the alliance in front of other world leaders.
As Foreign Policy noted when it first reported Melville's resignation on Friday, NATO countries are fearful that Trump will snub them further at an upcoming summit - before he meets personally with Putin.
The State Department confirmed that Melville announced his immediate resignation on Friday, without going into details as to why or answering questions about who now runs the U.S. Embassy in Estonia.
During more than three decades as a diplomat, Melville had served at U.S. embassies in Moscow, London and Berlin before President Barack Obama appointed him to the ambassadorship in Estonia in 2015.
Trump nominated a retired Navy admiral, Edward Masso, to replace Melville late last year - but withdrew the nomination last month for unknown reasons, according to Estonian public radio.
In a Facebook post obtained by The Post, Melville wrote that he had been planning to wait for a replacement to be approved before retiring from public service - but that his principles wouldn't allow him to continue serving under Trump.
So he will instead follow diplomats such as the U.S. ambassador to Panama, who resigned from the Trump administration last year "because my values were not his values."
"I suppose I could have stayed on for many more months," Melville wrote near the end of his Facebook message. "I do love Estonia, its wonderful people and beautiful landscape."
"But on balance, I'm glad not to be staying, for all the reasons I've just explained," he continued. "So I leave willingly and with deep gratitude for being able to serve my nation with integrity for many years, and with great confidence that America, which is and has always been, great, will someday return to being right."
The Washington Post's Michael Birnbaum contributed to this report.