Five psychiatry professors from various major universities are calling on Congress to declare President Donald Trump mentally unfit for office.

Their mission began almost immediately after Trump’s election, when three professors of psychiatry—one from Harvard University and two from the University of California, San Francisco—sent a letter to former president Barack Obama expressing their “grave concern” for the “mental instability” of the President-Elect.

"Our Constitution has provisions for removing any president who is unable to discharge the duties of office."

Questioning “his fitness for the immense responsibilities of the office,” they suggested that Trump should “receive a full medical and neuropsychiatric evaluation by an impartial team of investigators” before assuming office.

A few months later, other psychology professors created a group called “Duty to Warn,” holding a conference at Yale University to make the case that Trump’s “dangerous mental illness” is a threat to America.

One of the professors involved in that group, Bandy Lee, subsequently did an interview with Chauncey DeVega during which she claimed that the United States is in a state of emergency because of Trump’s mental disabilities, saying she feels compelled to speak out about the matter because “many lives and our survival might be at stake.”

[RELATED: Yale prof: Trump’s ‘mental impairment’ a ‘state of emergency’]

Lee, along with Columbia University psychiatry lecturer Robert Jay Lifton, M.D., has now joined forces with the three professors who signed the letter to Obama to write a new open letter, this time urging Congress to take steps to remove Trump from office.

The professors begin by referencing their previous public warnings about Trump’s “alarming psychological instability,” saying his “repeated failures to distinguish between reality and fantasy” and his “erratic responses to stress and crisis” have proven their point.

“The signs of the president’s unraveling are stark, and they are contributing to his inability to govern,” the letter continues, citing a litany of Trump’s supposed flights of insanity, including “his irrational, unilateral withdrawal from the world’s commitment to prevent catastrophic climate change” and “his vitriolic verbal assaults against anyone (especially any woman) who questions his actions or state of mind.”

[RELATED: POLL: Majority of profs think Trump will be impeached]

Asserting that “the power of the presidency has accentuated Mr. Trump’s failings with devastating effects,” the professors contend that “his tenuous relationship to reality” has caused actual harm to the United States, and is therefore grounds for his removal from office.

“Our Constitution has provisions for removing any president who is unable to discharge the duties of office,” the letter concludes. “For the sake of our country and the world, we urge our elected representatives to summon their courage so that lawful steps can be taken to end the Trump presidency.”

The professors who wrote this letter, along with nearly two-dozen others, are currently working on a book called The Dangerous Case of Donald Trump, which will purportedly attempt to answer the question, “what is wrong with him?”

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