As groups of Trump supporters across the country gathered in defiance of social distancing rules to demand an end to stay-at-home orders, a prominent psychiatrist and expert on violence argued the president’s influence over the protesters made him more dangerous to the country than ever before.

“What I noticed in the behavior of the president is what I have seen in the dynamics of individuals who become violent, as well as those who provoke violence in others,” Dr. Bandy Lee, a forensic psychiatrist at Yale School of Medicine, told Jim Braude on WGBH News’ Greater Boston Monday.

Lee, who was not speaking on behalf of Yale, referred to a recent series of tweets from the president urging his supporters to “liberate” their states and save the Second Amendment.

“I saw what he was doing, calling his followers to liberation, especially when they are suffering from the intense lock-downs and loss of jobs,” Lee said. “And now he is using that to test his ability to call out his armed troops, if you will.”

Lee attributed the president’s behavior to what she calls a “mental incapacity” to do his job as president.

“When someone lacks capacity, [they have] difficultly taking in information, taking in advice, processing that information and making sound, rational decisions,” she said. “And those are the kinds of things we are seeing in the president.”

Lee — who is also the author of a textbook called “Violence” and the editor of “The Dangerous Case of Donald Trump” — urged people not to conflate what she sees as the president’s deficiencies with mental illness, which alone does not imply unfitness for office.

“Mental illness does not define incapacity,” she explained. “In fact, it almost has nothing to do with dangerousness, either.”

But in Trump’s case, Lee said, she and some of her colleagues have seen a pattern of dangerous behaviors — especially in the past year.

“After the Mueller Report was out, when the impeachment proceedings were happening, we felt that the president would engage in dangerous acts,” she said. “And he has, such as withdrawing troops from Northern Syria or commanding the assassination of [Iranian General Qasem Soleimani].”

“Now, under this coronavirus pandemic, we have found it necessary to also alert Congress. More urgently than ever, in fact,” she added.