[SJackson]

When the facts are on Medved's side, he argues facts. When he switches to ad hominum attacks it's a sure sign he has nothing.

Like it or not, the credibility of a source is relevant, not an ad hominum attack.

[Hugin]

Since Corsi documents his sources, and they are public ally available, why is it relevant to the argument? And it most certainly is an ad hominum attack, regardless of the reason.