the.com/fence sitter
someone who refuses to pick a side until the winner is obvious, then claims they knew all along.
means a person who avoids committing to a position or decision, often to dodge conflict or hedge their bets.
from from the literal image of straddling a fence between two properties, unable or unwilling to land on either side; the phrase took off in 19th-century american political slang describing voters who wouldn't declare loyalty to a party.
political originpopularized describing undecided 1800s us voters
literal imagestraddling a boundary, committed to neither yard
psychology termrelated to what's called decision avoidance