Mr Trump is different. The media attacks on him have been fast and furious. Yet he has defied electoral gravity because the blows are delivered by an institution that is distrusted and an elite political and business establishment that is detested.

Meanwhile, voters consistently tell pollsters like me that negative attacks do not work; they hate the ad hominem assaults. Mr Trump? He dines out on them. As his devotees see it, it is not Mr Trump going negative. It is him telling the truth. And when he fights back, he’s throwing punches on their behalf. He said something outrageous? “He’s simply raising an important issue nobody else has the courage to talk about.” He insulted someone? “That’s just him campaigning. He won’t do that as president.” He changed his position? “That was a long time ago. Everyone’s entitled to change their mind.” He doesn’t have many policy specifics? “He doesn’t need them. He’ll surround himself with smart people.” They will justify any action, explain away any contradiction, and dismiss any criticism because they are so personally and passionately invested in him.

And here is the prediction that will furrow brows on both sides of the Atlantic. Mr Trump’s supporters today will be Mr Trump’s supporters next November if he is still a candidate — no matter what party banner he runs under. Half will follow him out of the Republican Party if he breaks his promise and declares as an independent. For better or worse, his supporters will follow him to the ends of the Earth — or to the White House. Whichever comes first.