The unnerving vision of Donald Trump one day getting within reach of the nuclear codesis bad enough, but the job specification of commander in chief demands more than just a cool head and stable personality. The president also needs the ability to handle and control hotheads who can appear around them in the midst of crisis.

To be sure, today’s Pentagon generals seem to be a suitably sober bunch, chastened by the cost in lives and treasure of recent wars. Sometimes, though, a general long-seasoned in battle and without doubt possessed of great personal courage can be the last person a president facing Armageddon should listen to.

Probably the most terrifyingly instructive example of this species appeared in the person of Gen. Curtis LeMay, the chief of staff of the Air Force and head of the Strategic Air Command during the Cuban Missile Crisis in 1962.

President John F. Kennedy and his brother, Attorney General Robert Kennedy, were facing a volatile and unpredictable threat from the Soviet leader, Nikita Khrushchev, who had covertly set up missile bases in Cuba. As the crisis built, the Kennedys found themselves in a minority that held to the belief that a diplomatic solution could head off a military confrontation that would easily trip into a nuclear war.

The Joint Chiefs of Staff, other generals, and some elder statesmen were demanding airstrikes against the Russian bases in Cuba before the missiles became operational, to be followed by an invasion. Kennedy feared that, at the minimum, these American actions would lead to a Soviet attack on West Berlin. ...