One of the joys of parenthood is that you see the world again through fresh eyes. Almost the same could be said of observing Donald Trump’s learning curve. Did anyone know how complicated US healthcare could be? Were people aware that Abraham Lincoln was a Republican? Who knew that North Korea was not at China’s beck and call?

The good news is Mr Trump’s curve is often vertical. Some of his crazier positions have been discarded. The bad news is that Mr Trump’s shifts require constant vigilance. For the next four or eight years, global peace of mind will depend on Mr Trump having the right advisers at hand when it matters.

Things go wrong when moderating influences are absent. On Monday, Mr Trump called Recep Tayyip Erdogan, Turkey’s autocratic president, to congratulate him on a narrow referendum victory that is in dispute. It is no coincidence this ill-advised call took place while HR McMaster, Mr Trump’s national security adviser, was out of the country. The president’s most incendiary daytime tweets often come out on a Saturday, when his son-in-law, Jared Kushner, is observing the Sabbath. The others are issued at night when Mr Trump is alone. He is the first president since Franklin Roosevelt in the 1940s to go to bed and wake up alone. Until now, his wife Melania has shown no sign of wanting to join him in Washington. Beware Mr Trump when he is alone with the world.