It's actually his ability to play Mr. Bennett so well that will ultimately make his President Snow so disturbingly evil. Because Snow doesn't come across as overtly evil. It's more subtle. He's the consummate politician. He is all smiles and charm and charisma and grandfatherly, but underneath all of that is the evil, cloaked and hidden. The smell of roses covering something sickly is used in the books as a description that fits his personality as well. The innocent rose disguising the moral decay within. The true evil of President Snow lies in his ability to cloak that evil, but not quite completely... a hint of it creeps through. I think Donald Sutherland will be perfect for this role requiring a lot of complexity and nuance.

