From James Comey in NY Times, 5/1/2019

Amoral leaders have a way of revealing the character of those around them. Sometimes what they reveal is inspiring. For example, James Mattis, the former secretary of defense, resigned over principle, a concept so alien to Mr. Trump that it took days for the president to realize what had happened, before he could start lying about the man.

But more often, proximity to an amoral leader reveals something depressing. I think that’s at least part of what we’ve seen with Bill Barr and Rod Rosenstein. Accomplished people lacking inner strength can’t resist the compromises necessary to survive Mr. Trump and that adds up to something they will never recover from. It takes character like Mr. Mattis’s to avoid the damage, because Mr. Trump eats your soul in small bites.