But Mattis isn't a parent, so the metaphor breaks down quickly; a parent has responsibility because they're the legal guardian of a child (either having created it or taken it on willingly through adoption, etc). Mattis is more like an employee, who has no ethical or legal responsibility for his boss beyond giving advice ethically and performing the duties of his job. At some point, if the boss is acting counter to the employees own ethics, the most ethical choice is to quit while stating as such and thus not provide further help to an enterprise that is doing what you think is the wrong thing. Yeah, I would prefer that Mattis were there for my peace of mind, but I don't think he did the wrong thing.