If there is a single unifying thread in Trump’s splenetic surges, it is a visceral hatred of Barack Obama. It started early — with Trump becoming a leader of the ‘birther’ conspiracy theory — and it’s got worse with every passing year. He’s still obsessed with Obama and everything he stood for and did as president. (Including appointing Hillary Clinton as Secretary of State.)

So what’s at the root of this psychosis?

Answer: Obama’s elegant mockery of him at the 2011 White House Correspondents’ Dinner. For a narcissist like Trump, this was a truly traumatic experience. And now the US — and the rest of the world (apart from Russia) is paying for it.

LATER Some people think that the humiliation at the dinner was the reason Trump decided to run for President. But that seems unlikely — as the WashPo pointed out. Also, I seem to remember that he gave an interview years ago to Polly Toynbee in which he talked about running.