In my last post, I made the argument that Clerics belong in D&D, especially considering the historical simulation roots of the game. However, there are the arguments that the mace-wielding battling bishop is not very historical and that Clerics were only born out of the need to fight the vampire Mr. Fang. This is where the war gaming roots of D&D become important.
War games are by their very nature abstract, and, when it comes to those meant for public consumption, are meant to entertain. This results, on the one hand, in arbitrary mechanical and mathematical representations of all kinds of things like troop size, training, skill, technology, speed, range, etc. On the other hand, in order to make the game entertaining, there is also a need to balance things out so that one side, or one troop choice, etc., has advantages and disadvantages that create interesting game play. It is out of this perspective that D&D has the classic Fighting Man and Magic User. One choice allows all weapons and armor, but no magic while the other choice forgoes all weapons but the most basic and all armor in order to be able to use magic. This concept of classes does not come from literature, where magic wielding characters of all stripes are seen wielding swords and even wear armor — its roots are in war gaming.
This is where the Cleric begins to make sense. A need arose within the game — Mr. Fang and how to defeat him — and new mechanics had to be created. Given the historic pedigree of Christian adventurers, the medievalism of the game and the iconic image of vampire hunters wielding a cross to fend off the undead, it made sense for the new class to be some kind of psuedo-Christian adventuring priest. Given the mechanical balance of Fighting Men and Magic Users, it made sense that the Cleric should sit somewhere in-between:
Clerics gain some of the advantages from both of the other two classes (Fighting-Men and Magic-Users) in that they have the use of magic, armor and all non-edged magic weapons (no arrows!), plus they have numbers of their own spells. — Men & Magic
Note that the justification of "weapons that don't draw blood" is only inferred, not explicit. Rather, it is an easily defined category of weapons that arbitrarily limit the number of weapons a Cleric can use. The armor-clad, mace-wielding bishop may largely be absent from history, but from a war gaming perspective it just makes sense. So much so, that it has been with us since 1974.