At minimum, Washington needs a serious back-channel means of communicating with Pyongyang — something Tillerson apparently was exploring — so each side understands the other’s intent.

Trump, however, appears eager to reduce the U.S. options on North Korea to two: more presidential insults and threats (with the risk that this provokes a paranoid Kim into making a dangerous military mistake) or starting a massive, hugely destructive war.

On Iran, Trump’s detestation for diplomacy is equally dangerous.