I'm looking for a phrase for the situation where the person responsible for seeing a task is done is the person least likely to do the task themselves. For example you wouldn't make Bob responsible for ensuring everyone washes their cup because Bob is the worst culprit for forgetting to wash his own cup.
I feel like "Choosing the fox to guard the henhouse" is not quite right as there is malice and/or cunning implied in what the fox would do in the henhouse.
Is there a phrase or idiom for choosing a person who is inept or ill suited for the work in this way? The subject of the discussion isn't stupid, just the opposite of the person you want for this task.
Best Answer
How about wrong tool for the job?
If you want to take out a screw, you choose a screwdriver, not a hammer. This doesn't mean hammers are "stupid". They're great at driving nails. They're just ill-equipped (not designed) for removing screws.
And so it is with people. You need to choose the right "tool" for the job. If you want someone to improve housekeeping, you choose a neatnik, not a slob (or so conventional wisdom would have it).
So, if Bob is the worst culprit when it comes to washing his own cup, and you make him responsible for ensuring that everyone washes their cup, I could say, with some justification, "You chose the wrong tool for the job."
Wrong tool for the job has the same connotations as "the fox guarding the henhouse": the fox is the wrong tool for the job. Perhaps this is why you thought of "the fox guarding the henhouse" when pondering your own question.