The toxic mix of Donald Trump’s overconfidence and insularity to which we called attention two years ago, in the book “The Dangerous Case of Donald Trump,” much to the chagrin of the American Psychiatric Association, has played out with lethal consequences in northern Syria. Trusting his “gut” over consultation with readily available American and allied military leaders, diplomats, and Middle East and security experts, Trump, in his “unmatched wisdom,” has triggered a catastrophic humanitarian crisis, and his move constitutes an irretrievable betrayal of Kurdish allies who carried the burden of the successful ground campaign against the Islamic State.

The Kurds are paying the immediate, dreadful price for Trump’s arrogance and unwarranted certainty. Our bill will come later.

Dr. Leonard L. Glass

Boston

Edwin B. Fisher

Chapel Hill, N.C.

Dr. Bandy X. Lee

New Haven

The writers are professors, respectively, at Harvard Medical School, Gillings School of Global Public Health at the University of North Carolina, and Yale School of Medicine.

Note from KBJ: Yes, because only a mentally ill person would want to save American lives.