General Discussion

All the way back to his first campaign, that should have been the strategy. When you look at Trump and understand that the narcissism isn't just an undesirable personality trait for him, it rises to the level of a pathology. It is a mental condition, a full blown psychological disorder. He is incapable of not responding to ridicule, it is as necessary for him to respond to it as it is for him to breath.

The Mayo Clinic's description of Narcissistic Personality Disorder:

https://www.mayoclinic.org/diseases-conditions/narcissistic-personality-disorder/symptoms-causes/syc-20366662

Look through that list of symptoms and tell me Trump isn't the poster child for NPD!!!

When viewed through that lens, the strategy to deal with him becomes obvious. Flattery from within his circle to manipulate him towards positive outcomes and ridiculing him from outside his circle to push him into wasting his time on relatively unimportant things and into making poor decisions and unforced errors on important issues.