Neither can Ulfric if I go by that final battle in Windhelm. For a man who knew the way of the voice he folded faster than a lawn chair under Rosie O' Donnell.
Yikes! Well, there goes breakfast, thanks for the image, man, I'm not going to eat properly for a week now.
Nobody, anywhere in the game, is all that well protected from the Dragonborn! You kill dragons, vampire lords, whatever gets in your way. Clearly, Ulfric knows his only chance is to get you on his side, and if he fails, a nuclear response won't even help his butt against the one and only Player Character.