Peculiar logic

If a rich man gets into politics, he's surely motivated solely by money, and can only see his office as an opportunity for graft.

If a career politician becomes rich while in office, he's a dedicated public servant and we mustn't question the fruits of his service.

... And I'm thinking of one of the subplots of The Mote in God's Eye: How do you transport a not-quite-prisoner who can credibly offer a planet as a bribe?  Put him in the custody of an officer who's so fantastically rich already as to be unbribeable.