Pretty simple. What kind of POD would have caused the United States to elect a fascist or neo-fascist president, and what group would have been most likely to put forth such a fascist president? I'm thinking either a much worse Great Depression causing the Silver Legion to come to power, or 9/11 being much more damaging and possibly with nuclear suitcase bombs. I'm probably wrong with the latter, though.
If a discussion on this topic already exists, please direct me to it.