Any given politician can be blackmailed for a bunch of different reasons. It is up to the politician to maintain his professional and legal responsibility to not give in to such tactics. Now, for something that is old news, Edwards did the right thing by not dignifying questions about his affair with a response. Let the topic die out, and fade away, as there are no legal ramifications of his actions.
Now this is a rhetorical question, but do you have to be consistently insulting? Just because I do not see things they way you do, doesn't make me any worse or better of a person than you.