But, his critics insist, Donald Trump plays a unique role here. And they are right; presidents are supposed to be a unifying symbol in times of stress, but Trump can barely go through the motions.

Both as a candidate and as president, he has used his extraordinary megaphone to push the envelope of acceptable discourse and behavior, not merely by the crudity of his attacks on his foes, but by his cultivation of a menacing swagger as a sign that “he fights.” He has openly encouraged violence against protesters at his rallies and celebrated the physical assault on a reporter who was body slammed. Perhaps inevitably, his supporters/followers have often modeled their language and behavior on his, especially as he has stoked anger against his critics and embraced conspiracy theories about their malevolent plans to destroy America.

In a nation of more than 300 million, there are more than a handful of unbalanced individuals who might take all of this both literally and seriously.