Trump is ranting about Curiel’s bias not because doing so is part of any kind of rational political strategy, but because he is going to lose the case. And if he loses, it must be somebody else’s fault. He’s not just talking about himself instead of something that actually matters to voters. He’s talking to himself, telling himself a story of how big a winner he is, no matter how often he loses. And he’s doing it in front of the entire country.
In a very basic sense, this is the emotional connection that Trump forged from the beginning of his campaign. Trump sees himself as a winner whose occasional setbacks are the result of other people’s unfairness or incompetence. He has connected with a slice of the voting public that sees America’s problems in similar terms: the fault of corrupt, incompetent, and disloyal elites. But successful political leaders — whether they operate within established norms or, like Trump, gleefully flout them — use that emotional connection for something larger. It’s the ground on which they build loyalty to a political program and organization.
Trump isn’t building anything. Indeed, he hasn’t built anything in a good long time; for decades, he’s been a marketer whose only product is his own mystique. And so it is with his political campaign. The purpose of the emotional connection he has forged is entirely personal: to reaffirm his own greatness, his own winningness.