Sit on the Fence

Documented in American English from 1828, already used figuratively rather than literally from its earliest appearances, which makes pinning down a single originating incident difficult. One theory pictures spectators literally sitting on a fence at a fight or contest, refusing to back either side; another simply notes that someone sitting on top of a fence can jump down on either side with equal ease. The phrase got a real boost in 1884, when a group of Republicans who backed the opposing Democratic candidate were mockingly dubbed "Mugwumps," birds supposedly sitting on a fence with their "mugs" on one side and their "wumps" on the other.