While at times it may seem to be so, one must remember that religion is almost never the cause of war.* It is, in fact, human nature.
Throughout history, man has made division after division among his follow man, in order to secure power for themselves, and sometimes their family. Also, it is rather obvious from history, that, almost as much as humans can’t stand to be weak, they can’t stand to see their neighbors rise above them. The Crusades, under the cover of a “Holy War,” were not, I believe, so much a byproduct of the European powers wanting more land and… power, but rather the cause was that the European powers could not stand that the were not in possesion of this holy land. The Muslims and to a lesser extent Jews living their could have been diehard Christians for all it mattered, some rival power would have declared war on them anyway. The whole idea of “siezing the Holy Land from the heathens” was merely propaganda to give some sort of credence or motivation to the troops.
Now, the whole Manifest Destiny thing the US went through during the 18th Century, while it was a more of a will-of-the-people thing than will of the government, on the surface it appears to be much like the Crusades. It was the Will of God that allowed the Americans to expand their country! It wasn’t their choice, it was the mandate of God! Please. I do not really know how to explain this, other than to attribute it to several reasons. One, that the non-white Mexicans were not fit to rule such fertile land as California or parts of Texas, and for the heck of it the prime railroad-laying land in between. Two, that with all this expansion of land in the North, the Southern slave states feared that their influence in the government would be lost, and, having no were else to expand, decided to take over parts of mexico and expand the South. Finally, the most simple and broad reason, the Americans wanted more land.
Often Religion is not a factor in war or other conflicts, or it is at least not the catalyst. More often it is ethnic, racial or cultural, with the “godless heathen” put at the end as if to say that the inferior enemy could never be a true follower of the X faith. Only, really, in cases such as Ireland is religion the main sticking point, but that is more because they couldn’t find anything else to hate them over, so they went with that. Religion is a very odd thing because it doesn’t matter how you look, it is impossible to ascertain ones religion simply from appearence. In terms of hate, it is often put into the back seat, made into an appendage to some other difference.
Even in Nazi Germany, the Jews were not hated for their religion, but because they were an inferior race, unfit to live, or even die in dignity. Judaism was the religion of these inferiors, and that was how you could tell them apart, because despite all the propaganda, most people knew Jews looked like them and not like the stereotypical Jew portrayed by the Nazi media. It has always been my belief that the Nazi’s thinking regarding the Jews went something like, “They were not inferior because they were Jews, they were Jews because they were inferior.” Religion was not a direct catalyst in this situation. Rather, it was jealousy on the part of the Germans who saw these fabulously wealthy Jews in so many positions of power, and sought to find some difference between them and these wealthy few, something to create an us vs. them platform to gain support of the populace and take over the wealth of these Jews. Unfortunately, these antics brought to a head all the residual antisemitism of the past 2000 years and led to the Lagers. IIRC, however, the idea of creating a Jewish State in Madagascar was heavily considered by many in the Nazi hierarchy, though the realities of moving 4 million Jews to Madagascar soon became apparent and that idea was abandoned. Soon after, the idea arose of creating a Jewish State in Lublin, to be called ‘Lublinland’ but these were mainly pipe-dreams.
So in effect, religion is not the cause of all wars, or even very many. It is, however, used as a cover quite often, to give justification to the actions of whoever is invoking it.
As said before, corrections in the pursuit of knowledge are welcome. If needed, I can always add more information to my post, but I am tired now, so have fun.
Cervantes
*Except, of course, in that little town in Chidren of the Corn