When soldiers in the First World War shot themselves in the foot, they did so because the harm they did themselves (injured foot) was preferable to what would happen to them if they were not injured (going over the top). So the phrase “shooting yourself in the foot” means to do something apparently injurious to yourself, in order to achieve a greater overall benefit. (It does not just mean doing yourself harm.)
So what did Condoleezza Rice mean whan she said last week that sanctions against Latin American countries
were “sort of the same as shooting ourselves in the foot.”
Or does the original saying derive from shooting oneself accidentally in the foot while holding a gun pointing downwards? See a possible dictionary definition. Anyway, I found this old geek joke while googling the phrase. Much more amusing.
I didn’t know Cambridge even published a dictionary …
I think the phrase implies an idea that backfires (because being shot in the foot really sucks?). I always thought it meant a deliberate action that backfired, but dictionary.com says it derives from accidental shootings… http://dictionary.reference.com/search?r=2&q=shoot%20oneself%20in%20the%20foot