Ha ha at the "elites" choosing who to burn 
There are six Bonfire Societies, and they each choose which effigy to build and burn. But they are very in-step with local thinking, so spectators usually thoroughly approve. We don't get to see them until the night of the 5th, so its a very exciting part of the evening and provokes a lot of speculation.
No one really knows when it started. The earliest documentary evidence is from the start of the 19th century, but presumably it had been going on in some form long before that. As to why it endures - not sure really, but there are lots of different 'strands' to it: the celebration of deliverance from the Gunpowder Plot, a big dollop of anti-catholicism (not so nice that, so it tends to be played down, though we still burn Pope Paul V annually), remembrance of the protestant Marian Martyrs burned in the town in the 16th c., remembrance of the fallen in the wars, and a bloody minded, independent, protesting streak that seems to be in the towns DNA. The local motto is "Sussex won't be druv" (i.e.driven, or told what to do).
We're all terribly proud of it, and it's bigger than Christmas here.
I'll shut up now, as I could bore for England on the subject, and this thread is meant to be about the US election, but here's a link with lots more info on it, if anyones interested.