(CNN) A foreign service officer resigned from the State Department effective Thursday, writing in a blistering op-ed in The Washington Post that he could no longer serve in "The Complacent State," particularly in the wake of the El Paso mass shooting.

Chuck Park wrote in the op-ed that during his almost 10 years in the foreign service he "worked to spread what (he) believed were American values: freedom, fairness and tolerance."

"But more and more I found myself in a defensive stance, struggling to explain to foreign peoples the blatant contradictions at home," he wrote.

Park said that after the election of President Donald Trump, he had remained "complacent" and had "let career perks silence (his) conscience."

"I let free housing, the countdown to a pension and the prestige of representing a powerful nation overseas distract me from ideals that once seemed so clear to me. I can't do that anymore," Park wrote.

"My son, born in El Paso on the American side of that same Rio Grande where the bodies of Óscar Alberto Martínez Ramírez and his daughter were discovered, in the same city where 22 people were just killed by a gunman whose purported 'manifesto' echoed the inflammatory language of our President, turned 7 this month. I can no longer justify to him, or to myself, my complicity in the actions of this administration. That's why I choose to resign," he said.

In an email to CNN, Park clarified that he made the decision to resign before the El Paso shooting, "though it certainly reaffirmed it."

Writing in the Post, Park noted that he has not seen an "organized resistance from within" to the Trump presidency, but rather "The Complacent State."

"Among my colleagues at the State Department, I have met neither the unsung hero nor the cunning villain of Deep State lore," he wrote.

"One thing I agree with the conspiracy theorists about: The Deep State, if it did exist, would be wrong," he said, noting that foreign service officers pledge to serve at the pleasure of the President -- or else they should quit.

Park told CNN that the reception to the piece has been "almost uniformly positive" with "some mea culpas from personal friends still in the service; some offers of support as I transition to whatever is next."

Asked why he chose to highlight his resignation in such a public way, Park said, "I meant the piece more as allocution than a call to action or challenge to people in a similar situation, though most have read it as the latter."

"Though we are keeping the metaphorical lights on, we are not the heroes that some make us out to be. The real 'resistance' must come from American voters in 2020," he said.

Park's cutting public rebuke is the latest by a former diplomat of the sitting President.

John Feeley, the former US ambassador to Panama, retired in March 2018. He wrote in The Washington Post that he made his decision shortly after the deadly rally in Charlottesville, Virginia, noting "The President's failure to condemn the white supremacists and neo-Nazis who provoked the violence made me realize that my values were not his values."

"I resigned because the traditional core values of the United States, as manifested in the President's National Security Strategy and his foreign policies, have been warped and betrayed. I could no longer represent him personally and remain faithful to my beliefs about what makes America truly great," Feeley wrote.

Roberta Jacobson, who resigned as US ambassador to Mexico in May 2018, told NPR shortly after that Trump's "zero-tolerance" immigration policies were "draconian and frankly un-American."

She said "part of the impetus" for her departure "was the increasing difficulty I had in trying to defend some of these policies and in trying to work with a Mexican government that was quite keen to work with us, only to see that sort of blown up periodically by tweets or rallies about the wall or about, you know, characterizing Mexicans, which was not what I experienced."

Jacobson also penned a New York Times op-ed later that year detailing the "disorder" of working under the Trump administration and warning of deteriorating trust between Mexico and the US.

James Melville stepped down as US ambassador to Estonia in 2018 because he "could no longer support President Trump's policies and rhetoric regarding NATO, our European allies and Russia."