World War I, religion died in the 20th century, science triumphed in religion in the

[Belacqua]

During the First World War, the Entente formed a union not on a religious basis

I guess I don't see this as unique to WWI.

The Franco-Prussian War and others prior to WWI were not aligned along religious lines. 

Even the Thirty Years War began, in part, for religious reasons but pretty soon turned into a war between two Catholic blocks (Hapsburgs vs. France) for political power.

Or am I not understanding you?