From last week’s New Yorker article on Rod Blagojevich:
“Jack them up!” Blagojevich tells one aide while discussing two well-to-do Chicago attorneys whom he feels haven’t donated enough money.
My advice to you, if you have trouble deciding when to use who and when to use whom, just use who for both subject and object. It will simplify your life, ease your mind, and put you ahead of the game when the dictionaries finally attach obs. to whom.
If, however, you persist in using both forms, keep in mind that when the pronoun is the subject of a clause — who haven’t donated enough money springs to mind — you are not allowed to use whom.