It occurred to me some time ago that the self-centered person tends to be lacking in self-interest. Maybe it is a matter of lacking an objective perspective, of being able to regard oneself as distinct from one’s environment. That is, the self-centered person lacks a sense of self, perhaps because sensations are based on comparisons.
Anyway, if a person has no self-interest then s/he can’t have a conflict of interest. Right? If there is nothing there, there is nothing to conflict. That might explain the Republican failure to recognize that public servants are not supposed to serve special interests, including themselves.