It would take a considerable ammount of force to kill someone just by striking the throat...
On the other hand, there are some vital points in this area that can kill with a little less than full force.
Moderate force at the side of the throat (the corotid sinus in particular) is all it takes to deliver a knock out while a hard strike would be deadly, but your aim would have to be accurate.

Really, it all depends on where and how hard the strike is delivered whether or not it would be lethal.