This sort of thing doesn't happen because of just one person. The situation reminds me of the (fictionalised) account of the Roman Empire in "I Claudius": the narrator remarks that corruption had well set in in the centre under Tiberius, but everything looked ok to those outside the City until the madness of Caligula. That's not to say that the majority of Americans are bad people, but the political culture must have been diseased for some time for this to be possible.