"You don’t have to be a follower of Jung to discern something deeply symbolic in these beheadings by self-appointed executioners. To sever the head from the body, at least nowadays when we have a more refined sensibility, is not merely to kill: It is symbolically to annihilate not only the biological existence of the beheaded, but the very thoughts he has had during his lifetime. To throw away a head as if it were a worthless inanimate object is to deny in the most categorical way possible any ideas that it might have had while living. It is to imply that only correct thoughts can henceforth be allowed to exist in heads, the kind of thoughts that the executioners themselves have; not until there is unanimity in thoughts, they imply, will our heads rest easy on our shoulders.
One hardly needs to emphasize the terrifying demonstration effect of the decapitation of supposed infidels by people to whom plenty of bullets are available as an alternative, swifter, and more certain method of procuring death. We conclude, as we are intended to conclude, that these are fierce and ruthless people whose belief in their own desert-tribal righteousness is unshakable. We should never forget that to commit barbarity in the name of righteousness is one of the greatest joys known to man — or at least to many men — and not just to Islamists, though at the moment it is they alone who have the courage of their barbarity, and rejoice publicly in it." - National Review.
Didn't Foucault make a similar point, somewhere, in Discipline and Punish?