Thanks to Siris for putting us in mind of Plato on this election day.
Socrates, in Plato’s Gorgias:
No, Callicles, the very bad men come from the class of those who have power. And yet in that very class there may arise good men, and worthy of all admiration they are, for where there is great power to do wrong, to live and to die justly is a hard thing, and greatly to be praised, and few there are who attain to this. Such good and true men, however, there have been, and will be again, at Athens and in other states, who have fulfilled their trust righteously; and there is one who is quite famous all over Hellas, Aristeides, the son of Lysimachus. But, in general, great men are also bad, my friend.