Mugwhump

I haven't heard this phrase in awhile and was
curious of it.

"...mug on one side whump on the other."

Today I saw the words spoiled mugwhumps in
Charlie Daniels'
- Open Letter To The Hollywood Bunch,
using the word "mugwhumps."

What exactly is a mugwhump?

It was a wit's observation during the 1884 campaign that a mugwump was a fence-sitter, with hig mug on one side and his wump (comic mis-pronunciation of rump) on the other

Thank you very much for this explaination!!
;)Hart