As Trump's mental state comes increasingly into question, I'm sure we'll hear a lot about the #Goldwater rule — part of the code of ethics of the American Psychiatric Association (APA), stating that "it is unethical for a psychiatrist to offer a professional opinion unless he or she has conducted an examination and has been granted proper authorization for such a statement."

This rule is often presented to the public as if it were supported by a broad, overwhelming consensus of the psychiatric profession and other mental health professions. That is not true. The rule has been subject to intense controversy within these professions from the start. And, from the start, it has been highly politicized, used in high-profile contexts to shield right-wing public figures from scrutiny:

https://en.wikipedia.org/wiki/Goldwater_rule