The letter decries the current culture at the State Department, a subject that has featured prominently during the House Democrats' impeachment proceedings. Secretary of State Mike Pompeo has received criticism for not adequately protecting the career diplomats enmeshed in the impeachment inquiry. President Donald Trump has branded several of them as “never Trumpers.”

“In already difficult times, the Department of State is experiencing what I and many believe is the worst and most profound moral crisis confronting career professionals and political appointees in the Department’s history,” Chang wrote. “Department morale is at its lowest, the professionalism and collegiality — once a hallmark of the U.S. diplomatic service — has all but disappeared.”

Chang also takes the State Department to task for not defending her.

“A character assassination based solely on innuendo was launched against me attacking my credentials and character,” she said. “My superiors at the Department refused to defend me, stand up for the truth or allow me to answer the false charges against me.”

A spokesperson for the State Department didn’t immediately respond to a request for comment. A spokesperson for Chang said she didn’t have any further comment beyond the letter and a rebuttal document she wrote about NBC’s story . NBC didn't immediately respond to a request for comment about Chang's push back.

NBC reported last week that Chang had misleadingly claimed in her official bio that she was an “alumna” of Harvard Business School when in fact she only attended a seven-week course there. It also reported that Chang had even created a fake Time magazine cover featuring her own image.

In her rebuttal, Chang notes that she never claimed to have earned a degree from Harvard. A Harvard Business School spokesperson told NBC that the school lets people who attend certain executive education programs claim “alumni status,” even if they didn’t get a degree.

Chang’s rebuttal also says the Time cover originated when a friend of hers commissioned an artist, Pierre-Yves Daygot, to create “a piece with her on a Time Magazine cover.” The friend acted without telling Chang, the document says.

POLITICO NEWSLETTERS POLITICO Playbook Sign up today to receive the #1-rated newsletter in politics. Sign Up Loading By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

After that, the rebuttal says, “an enthusiastic fan online went one step further and used an app to make a fake magazine cover with Ms. Chang’s actual image superimposed on the cover which was subsequently circulated online.”

The document also says that Chang didn’t give any permission or had any knowledge that the fake cover would be used during a public access TV interview for Houston Community College.

Chang joined the State Department in late April and was later nominated for a job at the U.S. Agency for International Development, where she would have overseen a budget of more than $1 billion and the development agency’s work in Asia.

But she withdrew her nomination for that job in early September with no public explanation. NBC reported that the Senate Foreign Relations Committee had asked for more documents and information on her career background.

Chang said that when lawmakers raised questions, the State Department again reviewed her application materials and “found that she in no way misled officials during the investigation.”