back the wrong horse

The phrase "back the wrong horse" refers to supporting or investing in something or someone that ultimately turns out to be unsuccessful or a poor choice. It originates from horse racing, where bettors place their bets on horses, hoping to win. If someone backs the wrong horse, it means they have wrongly bet on a horse that doesn't perform well or doesn't win the race. In broader contexts, the phrase alludes to supporting the wrong idea, person, project, or cause, implying that one has made an incorrect or detrimental choice.