"Trump’s worldview offers no limiting principles when it comes to the use and abuse of power. "

Gerson makes this very strong statement and by so doing demonstrates that his opinions have very limited value.  Why?  Because Gerson is not in Trump's head.  If he wanted to determine whether Trump has principles limiting the use and abuse of power, he must ask him.  That is the only way to know.  This media tendency of telling us based on inference rather than direct interrogation is flawed.  In society in general, all to often we hear folks telling us what others think when they have not queried the party in question.  What we hear is inference, only inference, which reveals more about the inferrer than anything else.