I will now confess my own utopia. I devoutly believe in the reign of peace and in the gradual advent of some sort of socialistic equilibrium. The fatalistic view of the war function is to me nonsense, for I know that war-making is due to definite motives and subject to prudential checks and reasonable criticisms, just like any other form of enterprise. And when whole nations are the armies, and the science of destruction vies in intellectual refinement with the science of production, I see that war becomes absurd and impossible from its own monstrosity. Extravagant ambitions will have to be replaced by reasonable claims, and nations must make common cause against them.

The Moral Equivalent of War (1906)