Policy gets in his way. If he doesn't like someone, he fires them. If he thinks Jerusalem should be the capital of Israel he recognizes it as such. If he feels like pissing off North Korea, he does it. If he feels like saying something that is opposite of what he said last week, he says it. It's that simple. He does what he feels like doing when the urge hits him. If you understand this, you understand Trump and hopefully you understand the problems that poses for the nation. However, Trump's president is not about the nation, it's about Trump.