Religious belief and war

This morning as I was reading the newspaper (as is my regular practice) I came across yet another letter to the editor spouting off how religion is the root cause of most, if not all, wars and international conflicts.  This seems to be a common refrain lately from atheists, in particular, and it is beginning to get annoying.

That wars have been fought (and continue to be fought) with religious motivation or in the name of God is unquestionable.  But to assert that religion is the root cause of the majority of violent conflict is less certain, to my mind. One need only go back to the last century for examples. 

I would suggest that the 20th century is going to be remembered by two major ideologies; fascism and communism. 

Fascism's religious roots were tenuous at best. Yes, Hitler's version, is particular, targeted a specific religiously identifiable group but his hatred of them went far beyond religion.  Jews were targeted regardless of their personal religious beliefs (even those who had converted to Christianity or had no faith at all). His hatred was racial more then religious in orientation. 

Communism had no religious roots at all.  Indeed, communism seemed determined, at least in its earlier manifestations, to pull out all religious roots of any kind.  No other ideology caused more deaths in the 20th century.  Even fascism cannot claim as many victims.

Yes, there were some wars that had religious roots in the last 100 years. But a quick look at history might conclude that atheism caused far more wars and claimed far more victims in the 20th century than religion did.  This is not excuse those who use God to justify their bloody deeds.  But I would urge atheists to be more intellectually honest about the consequences of religious belief and tone down the rhetoric.