In the first few months of his presidency, Donald Trump surrounded himself with a certain sort of ramrod military man: John Kelly, Michael Flynn, H.R. McMaster and Jim Mattis. These men had or appeared to have the kind of manly virtues and bearing that Trump likes to see in himself: courage, toughness, combativeness.

But when you look at how someone like, say, Jim Mattis forged his character, you realize that he is actually the exact opposite of Trump. Mattis built strengths and virtues through the steady application of intense effort over decades. Trump is a man who has been progressively hollowed out by the acid of his own self-regard.

Mattis is a man who is intensely loyal to others and attracts loyalty among those around him. Trump is disloyal to others and attracts disloyalty in return.

The contrast between how these two men were forged is so stark that it throws into relief how character is and isn’t formed.