How are we to explain the Donald Trump phenomenon?

How are we to explain the Trump phenomenon? A good friend (well to the right of me) who lived in Houston for many years went back recently to look up old friends, all wealthy and successful. He was astonished to find that many of them seemed to think they were victims of oppression, living under some sort of tyranny. ‘They’re off their rockers,’ was his considered opinion. On a couple of recent occasions I have had a little glimpse of this. On a train from London to Edinburgh the other day, I overheard a conversation between two American tourists and an academic looking Scotsman. One of the Americans was calmly explaining why it was necessary to build a wall along the border with Mexico and the Scotsman was going quieter and quieter as he realised where the trail was leading. And on a plane to France three weeks ago, I came across a garrulous, widely travelled American who was an expert on bees.