There is something we all know which can only be rendered, in an appropriate language, as realpolitik. As a matter of fact, it is an almost insanely unreal politik. It is always stubbornly and stupidly repeating that men fight for material ends, without reflecting for a moment that the material ends are hardly ever material to the men who fight. In any case no man will die for practical politics, just as no man will die for pay. Nero could not hire a hundred Christians to be eaten by lions at a shilling an hour; for men will not be martyred for money. But the vision called up by real politik, or realistic politics, is beyond example crazy and incredible. Does anybody in the world believe that a soldier says, 'My leg is nearly dropping off, but I shall go on till it drops; for after all I shall enjoy all the advantages of my government obtaining a warm-water port in the Gulf of Finland.' Can anybody suppose that a clerk turned conscript says, 'If I am gassed I shall probably die in torments, but it is a comfort to reflect that should I ever decide to become a pearl-diver in the South Seas, that career is now open to me and my countrymen.'
Materialist history is the most madly incredible of all histories, or even of all romances. Whatever starts wars, the thing that sustains wars is something in the soul; that is something akin to religion. It is what men feel about life and about death. A man near to death is dealing directly with an absolute; it is nonsense to say he is concerned only with relative and remote complications that death in any case will end. If he is sustained by certain loyalties, they must be loyalties as simple as death. They are generally two ideas, which are only two sides of one idea. The first is the love of something said to be threatened, if it be only vaguely known as home; the second is dislike and defiance of some strange thing that threatens it. The first is far more philosophical than it sounds, though we need not discuss it here. A man does not want his national home destroyed or even changed, because he cannot even remember all the good things that go with it; just as he does not want his house burnt down, because he can hardly count all the things he would miss. Therefore he fights for what sounds like a hazy abstraction, but is really a house. But the negative side of it is quite as noble as well as quite as strong. Men fight hardest when they feel that the foe is at once an old enemy and an eternal stranger, that his atmosphere is alien and antagonistic, as the French feel about the Prussian or the Eastern Christians about the Turk. If we say it is a difference of religion, people will drift into dreary bickerings about sects and dogmas. We will pity them and say it is a difference about death and daylight; a difference that does really come like a dark shadow between our eyes and the day. Men can think of this difference even at the point of death; for it is a difference about the meaning of life.
Update: I should be clearer.
Will a cosmopolitan fight to defend his "home?" Will a man be willing to risk his life to protect an economic union?