If communication and presentation is one of a key attributes you need for a job (world leader in this case) then of course stuttering will make it almost impossible, but that doesn't mean that other important proffesions are hard to do for stutterers. Also fact the poeple stutter makes them automatically choose anything but proffesion where it's all about communication skills, which why you don't see any stutterers in these positions, but theoretically some may do it well. I'm not saying that stuttering is not that big of a deal tho