What is the origin of the idiom "back the right horse" and when to use it?

The idiom "back the right horse" originated in horse racing in the late 19th century. When betting on horses, it was important to support the contender most likely to win a race. Over time, the term took on a broader meaning to describe supporting or promoting the most favorable option in any situation.

What is the origin of the idiom "back the wrong horse" and when to use it?

The idiom "back the wrong horse" also originated in horse racing, where picking an underdog or lesser competitor to win a race could result in losing one's bet. Dating back to the late 1800s, the expression is now used to indicate supporting or endorsing someone or something that is very unlikely to succeed.