Donald Trump caused some harrumphing from commentators by refusing to show up at the latest GOP candidates debate this Thursday. He objected to Megyn Kelly as moderator on the grounds that there was too much bad blood (so to speak) between him and her for her to deal with him impartially, as a moderator shouldSome commentators thought Trump had shot himself in the foot there, making himself look petulant and childish. I think these commentators underestimate Trump's grasp of mass psychology, which I'm finding more and more impressive.What he actually did there was show control of the situation. Translated into words, his actions said: "You don't tell me which debates I'll show up at; I tell you. If you don't like it, you can go boil your heads."Blowing off the media like that goes down well with people who are inclined to vote for Trump, and with a great many others, too. Media folk don't realise how widely they are disliked. I'm looking for this little spat to generate yet another upward bump in Trump's poll numbers.