You asked: If Mattis wants to be President of the United States he can stow his feather duster and grasp a writing implement to start the paperwork. When he was trusted with DOD he misunderstood his role as a subordinate of Trump. Since he was relieved of his post he has failed to live up to his own standards. The motivator seems to be an abiding interest in maintaining forever wars. Also, Mattis is loved and cherished most by persons that believe all the positive press, the source of which is Mattis. As far as judgement, Mattis was an investor in Theranos. That was a ridiculous fraud worse than covid19, just not as widespread.

Everybody loves the image and what was not to love? The greatest fighting philosopher of our time? Hours long briefings from memory? Owner of a collection of scholarly books that numbers over 7000? Discovered on post in the rain at Christmas so a man could enjoy a meal with family? Knife hands, son?

How about an ounce of loyalty? Sometimes a commander makes a decision or keeps a promise and you fail to see the wisdom or the logic. He accepted the job thinking Trump was full of lies and this suited him just fine. The root of the problem was Trump intending to keep his campaign commitments. This is my guess why the air came out of that balloon.