Unstated assumption (1): Snyder's opponent does not have a questionable moral life.
Unstated assumption (2): Snyder's opponent must be a good candidate because his opponent has a questionable moral life.
Unstated assumption (3): Snyder's opponent has never had an affair during his married life.
Explanation: There is an assumption that a candidate and its opponent can be automatically described in opposites, in such a way that, if we know a piece of information about one, we can infer the opposite to be true for the other.