When Republican Sen. Bob Corker said last week that President Trump hasn't "been able to demonstrate the stability" needed for success and recommended he "move way beyond himself," it was news mostly because Corker has been one of Trump's key supporters in Congress.

Then James Clapper, who served in top intelligence jobs under former Presidents George W. Bush and Barack Obama, Wednesday morning questioned Trump's "fitness to be in this office" and said he was worried about the president's access to the nuclear codes. Clapper, who had a long military career, is a close friend and longtime colleague of Trump's Defense Secretary, Jim Mattis, a former Marine Corps general.

"If in a fit of pique he decides to do something about Kim Jong Un, there's actually very little to stop him," Clapper, former head of the Office of the Director of National Intelligence, said on CNN. "The whole system is built to ensure rapid response if necessary. So there's very little in the way of controls over exercising a nuclear option, which is pretty damn scary."

Until now, talk of Trump's erratic behavior and alleged narcissism was common on social media, late-night talk shows and among political opponents. But Trump's "fire and fury" comments about North Korea, a raucous rally in Arizona Tuesday and changing response to the violent protests in Charlottesville, Va., crossed a line for some Republicans and brought the conversation into the mainstream, even among some supporters.

A poll by the media and technology company Morning Consult over the weekend showed 55% of respondents said Trump was not stable.

Rep. Jamie Raskin, D-Md., a former constitutional law professor at American University, sponsored legislation in April that would set up an independent commission to determine if any president no longer has the physical or mental capacity to perform the duties of the office. The 25th Amendment to the constitution was ratified 50 years ago and calls for such a body but it was never set up.

The bill now has 28 co-sponsors and while more can't be added until Congress goes back into session Sept. 5, Raskin says there's been "a sudden spike after every acute episode" involving Trump's behavior.

"We need every tool in the constitutional tool kit to be able to deal with the unfolding and accelerating crisis of presidential power in America today," says Raskin.

Raskin notes the commission would also be in place if future presidents can no longer serve, but former New Hampshire Republican Sen. Gordon Humphrey urged the New Hampshire congressional delegation this month to support it because Trump is "impaired by a seriously sick psyche."

Speculation about the president’s mental health has also spawned a cottage industry of psychiatrists and authors opining on his fitness for office.

Yale forensic psychiatrist Bandy Lee is consulting with Democratic members of Congress and other psychiatrists about setting up an expert panel to advise Congress about Trump’s mental health. Lee, who said she is speaking out because of Trump's "dangerousness," edited the upcoming book The Dangerous Case of Donald Trump, to which 27 mental health professionals contributed.

Psychiatrist Allen Frances, meanwhile, who conceived of the diagnostic definition of narcissistic personality disorder, is coming out next month with his own book, Twilight of American Sanity: A Psychiatrist Analyzes the Age of Trump.

Read more:

Is chronic sleep deprivation impairing President Trump's brain, performance?

Stress, along with poor eating and sleeping habits, can challenge Trump

Will Trump's exercise and eating habits catch up to him as stress mounts?

President Trump rehashes Charlottesville response, bashes media at Phoenix rally

"Narcissistic personality disorder describes a debilitating need to project grandiosity so as to fight the inner feelings of low self-worth," says Lee, who works internationally on predictors and prevention of violence. "In extreme forms, narcissistic personality disorder is one of the disorders most associated with violence and is sometimes considered to be on the same spectrum as antisocial personality disorder, or sociopathy."

Frances says he doesn't think Trump has narcissistic personality disorder because it hasn’t caused him distress and impairment. Besides, he says, it's voters who should have the final word.

"He's not going to be defeated by a bunch of mental health workers saying he’s crazy," says Frances. "The way to defeat him is political."

Unlike all the empathic people who were "grieving openly about the terrible loss of life and threat of racism" after Charlottesville, "narcissists care more about being right or promoting a point of view," says psychiatrist Judith Orloff, author of The Empath's Survival Guide, which includes a chapter on narcissism.

"If a narcissist is forced to comply with a belief they don’t really have, they will go through the motions of 'saying the right thing' but then retract their statement when they have a change," says Orloff. "Narcissists aren’t open to being told what to do and they will rebel against that."

After Trump's declaration a week before Charlottesville that military action by North Korea would be met with "fire and fury like the world has never seen," Lee and four other psychiatrists who contributed to her book wrote a letter to all members of Congress.

"It no longer takes a psychiatrist to recognize the alarming patterns of impulsive, reckless, and narcissistic behavior — regardless of diagnosis — that, in the person of President Trump, put the world at risk," read the letter to Congress. "We now find ourselves in a clear and present danger, especially concerning North Korea and the president’s command of the U.S. nuclear arsenal."

Tony Schwartz, who co-authored Trump's 1987 book Art of the Deal but then became one of the president's sharpest critics, had stopped speaking publicly about him in recent months but appeared on MSNBC Sunday and discussed Trump's narcissism and impulsivity. Schwartz, who runs a human resources consulting firm called the Energy Project, also contributed to Lee's book. He tweeted Sunday that Trump is "prima facie mentally ill," noting that one doesn't need to be a psychiatrist to see it.

Schwartz says he decided to talk about Trump again because of North Korea and Charlottesville.

"I am deeply worried that Trump’s deep deficits and his resulting lack of self—regulation and judgment puts our country and the world at risk of obliteration," he says.

These may be scary — crazy, even — times, but many psychiatrists including Orloff refuse to comment directly about the president.

Some say it's unethical and unfair to those with mental illness to do anything close to rendering a clinical opinion on a public official's mental health. The White House seems to agree.

"With all the 'medical opinions' out there it's as if doctors have left their practices due to the Obamacare disaster and are now attempting careers in TV," White House press secretary Sarah Sanders said in a statement. "This is nothing more than another absurd attempt to attack the President. It did not work during the campaign, and it will not work now. "

The Goldwater Rule

Even so, a leading mental health association is loosening restrictions on some of its members.

The American Psychoanalytic Association last month gave members permission to discuss Trump's mental health publicly without concern for what's called the Goldwater rule. The psychoanalytic association has psychiatrist members, but also includes psychologists and other types of mental health counselors.

During the 1964 presidential campaign, the magazine Fact published the results of a survey about questions surrounding Republican Sen. Barry Goldwater’s mental health. After losing the race in a historic landslide, Goldwater sued the magazine and won a libel suit, an extremely difficult accomplishment for a public figure. Since then, psychiatrists have generally steered clear of analyzing the mental health of public officials.

"If one has questions about an individual's public behavior or capacity to govern, it's incredibly problematic to conflate with a mental illness," says psychiatrist and Harvard Medical School professor Rebecca Brendel.

Brendel is a consultant to the ethics committee of the American Psychiatric Association, which authored the Goldwater ethics rule. It says psychiatrist members of the American Psychiatric Association shouldn't offer a "professional opinion" about someone in the public eye … "unless he or she has conducted an examination and has been granted proper authorization for such a statement.”

Doing so when it's about an individual a psychiatrist hasn't treated diverges from established treatment methods, which include "careful study of medical history and first-hand examination of the patient," wrote psychiatrist and APA President Maria Oquendo.

Mental illness and physical illness "are not clearly so separate," says Brendel, who asserts that a medical assessment is required to make sure any apparent psychiatric symptoms aren't caused by medical problems.

Lee, who is no longer a member of the psychiatric association, says she respects the Goldwater rule but disagrees with what she says was an "expansion" of the rule issued in March that said a psychiatrist compromises "both the integrity of the psychiatrist and the profession" by offering any public opinions or comments about public officials.

She isn't making a diagnosis and agrees that doing so "from afar is not only unethical, but impossible."

"I only mention words and behaviors in relation to the president that point to his dangerousness," says Lee.

Trump the 'exceptionalist'

Michael Welner, who is board certified in psychiatry, forensic psychiatry, and disaster medicine — which includes managing patients exposed to nuclear radiation — says Trump has shown throughout his life that he is an “exceptionalist,” adding that “President Trump’s exceptionalism embodies healthy narcissism.”

Trump’s determination to win “dovetails with the ethos of American exceptionalism,” which Welner says contributes to his “success in the face of adversity despite others’ efforts to undermine him."

Besides, he says, anyone who raises the issue of Trump’s “potential dangerousness as a commander in chief,” needs to assess it compared to other presidents and former secretary of State Hillary Clinton.

He cited Obama’s “actual expansion of drone attacks" against non-specific targets and the enabling of the expansion of Iran's hostile nuclear weapon and missile program with billions of dollars of assets. And he asks, rhetorically, how to compare the risk of Trump’s relationship with Russia with Clinton’s "facilitation of the sale of uranium to nuclear Russia."

Politifact called the uranium allegation, which Trump tweeted about in March, "mostly false."

As a forensic psychiatrist, Welner has conducted risk assessments involving issues including sex offenses, of future violence, of workplace violence, of criminal re-offense and of return to Jihadist violence.

Any assessment of dangerousness of a president would have to have adequate access to personal and intimate communication, his choices and his vision, evidence historically for one’s dangerousness, and the circumstances of how that manifested itself, and relate to the context of the evaluation, in this case in the context of presidential power,” said Welner, noting that none of that is available to Lee.

Welner is also especially critical of any analysis based on the president’s behavior on Twitter.

“President Trump tweets for strategic impression management, to cheerlead American exceptionalism, and to pre-emptively manage the scheming of those who try to destroy him,” he said. “There is nothing intimate about that expression, but it is more of the theatricality of the President.”

While author and psychiatrist Frances doesn't think Trump is mentally ill, he agrees with those who think he's dangerous. Plus, as his book title suggests, he thinks the problem lies more with the voters.

"Trump isn’t crazy — but we are for electing him and not taking seriously the existential threats his policies pose to the health of the people in America, the future and the safety of the world," Frances says.