Last year, just before Halloween, Lewis Lukens, the deputy chief of mission at the U.S. embassy in London, visited a pair of English universities where he spoke about the importance of international cooperation, beseeching students not to “swipe left” on the historic “special relationship” between the U.K. and America. The speeches were—according to a copy of the remarks that Lukens provided to GQ—fairly anodyne, reprising all the things Americans and Brits had learned from each other, all the ways we’ve helped each other over the years, disagreements notwithstanding. At the time, things between the two countries had been strained—in part because President Trump had attacked British leaders, including Prime Minister Theresa May and London Mayor Sadiq Khan—but Lukens, the second-most-senior American diplomat to the United Kingdom, had a request for the students who had gathered to see him: “Don’t write off the special relationship.”

A week later, Lukens says, his boss, the U.S. ambassador Woody Johnson, an heir to the Johnson & Johnson fortune and a Trump political appointee, told him that he was done, firing Lukens from his post seven months ahead of when he was scheduled to leave for a new assignment. After nearly 30 years as a foreign service officer, his State Department career was over. The reason? Lukens says he had unwittingly committed a fatal error in his speech: He had mentioned former president Barack Obama.

Lewis Lukens, the former deputy chief of mission at the U.S. embassy in London, says he was fired by the Trump administration after a speech in which he complimented president Obama. Andrew Matthews / Getty Images

To open the speech, Lukens, who had worked for presidents of both parties, used an anecdote from his time as ambassador to Senegal to illustrate how allies can handle disagreements. He mentioned Obama’s 2013 visit to the country. “There was incredible excitement,” Lukens said in his speech. “He had a guard of honor, crowds shouting his name, street vendors selling WE LOVE OBAMA T-shirts. It was really amazing. And the president had really great talks with the Senegalese president, Macky Sall. They got on really well. But what I remember most of all was the disagreement they had—as friends.” Lukens explained that during the trip, an American journalist had asked Obama whether he had pressed the Senegalese leader on LGBT rights—a provocative topic in a country where same-sex relationships are criminalized as “unnatural” and where the LGBT community faces widespread discrimination. Lukens told the students that Obama handled the thorny question well. And then he moved on to the rest of the speech, not realizing the damage he’d done with a single anecdote. (When asked about the episode and Lukens’s ouster, the State Department declined to comment. The American embassy in London did not respond to a request for comment.)

This incident, which has not been previously reported, offers a stark example of the politicization of the foreign service under Trump. It’s also a grim illustration of how the administration—through three years of attempted budget cuts, hiring freezes, and grotesquely personal attacks—has eviscerated the country's diplomatic corps and put highly sensitive matters of national security in the hands of politically appointed novices. They are people like Gordon Sondland, the Trump donor who became America's ambassador to the European Union, who is now playing a starring role in the Ukrainian imbroglio that imperils the Trump presidency. It is no accident that impeachment hangs on a matter of diplomacy—and a stand-off between the country's top foreign policy professionals and the president's political allies, national security amateurs installed to do Trump’s bidding rather than the country’s.