Mental-health professionals typically say it is unprofessional to diagnose public figures from afar.

But some psychiatrists, psychologists and social workers are now insisting that desperate times call for desperate measures. Meaning: With President Donald Trump facing a scandal over his advisers' alleged secret ties to the Russian government, as well as the threat of North Korean nuclear-weapon escalation, they believe it is their duty to warn the country about his mental instability, even though they have not evaluated him in person.

The lack of a professional mental-health evaluation of the president "has resulted in a failure to lend our expertise to worried journalists and members of Congress at this critical time," Lance Dodes and Joseph Schachter write in a letter to the editor published this week by the New York Times. "We fear that too much is at stake to be silent any longer." Dodes is a retired Harvard Medical School psychiatry professor, and Schachter, who received his Ph.D. from Harvard, has held leading positions with the International Psychoanalytical Association.

They write in the letter:

"Mr. Trump's speech and actions demonstrate an inability to tolerate views different from his own, leading to rage reactions. His words and behavior suggest a profound inability to empathize. Individuals with these traits distort reality to suit their psychological state, attacking facts and those who convey them (journalists, scientists). ...

"We believe that the grave emotional instability indicated by Mr. Trump's speech and actions makes him incapable of serving safely as president."

33 other mental-health professionals have attached their names to the New York Times letter.

This letter to the editor, though stunning coming from eminent professionals and for its publication in the country's newspaper of record, is hardly unprecedented. A Change.org petition has asked mental-health professionals to sign if they believe Trump to be "psychologically incapable of competently discharging the duties of President of the United States." So far, the petition has more than 25,000 signatories.

"I am concerned about the bullying, harassment and lying that is being modeled by our now president," Melissa Sporn, a Virginia clinical psychologist, wrote on the petition.

The willingness of mental-health workers to set aside long-held professional norms and publicly weigh in on the president's mental state is sure to accelerate the discussion in the wider society.

"I know we're not supposed to bring this up -- but it is staring us brutally in the face," conservative New York magazine columnist Andrew Sullivan wrote over the weekend, referring to Trump's mental health. "I keep asking myself this simple question: If you came across someone in your everyday life who repeatedly said fantastically and demonstrably untrue things, what would you think of him?"

-- Douglas Perry