Do you think they may have threatened him and his family?
C'mon...Cheney was the biggest player in recent history, a very powerful and evil man.
Obama doesn't want to dismantle the system; just keep everyone at bay until the plan unfolds, or he has a better idea on how to manage it.
I mean, what would you do if surrounded by rattlesnakes?
Keep your eye on the biggest one.
Remember this, "Keep your friends close, and your enemies closer".