First off let's recognize the fact George Clooney is willing to take risks with movies that challenge him as an actor. Why else would he have chosen to star in Up in the Air, Men Who Stare At Goats or Syriana? Perhaps he thought his trademark charm would pull him through. He must have thought the role of "Jack" in the new film The American would be an even bigger challenge as he wouldn't be able to flash his trademark smirk, I mean grin.