What constitutes a nation is a sentiment and an instinct, a sentiment of similarity and an instinct of belonging to the same group or herd.  The instinct is an extension of the instinct which constitutes a flock of sheep, or any other group of gregarious animals.  The sentiment which goes with this is like a milder and more extended form of family feeling.  When we return to England after being on the Continent, we feel something friendly in the familiar ways, and it is easy to believe that Englishmen on the whole are virtuous, while many foreigners are full of designing wickedness.

Such feelings make it easy to organize a nation into a state.  It is not difficult, as a rule, to acquiesce in the orders of a national government.  We feel that it is our government, and that its decrees are more or less the same as those which we should have given if we ourselves had been the governors.  There is an instinctive and usually unconscious sense of a common purpose animating the members of a nation.  This becomes especially vivid when there is war or a danger of war.  Any one who, at such a time, stands out against the orders of his government feels an inner conflict quite different from any that he would feel in standing out against the orders of a foreign government in whose power he might happen to find himself.  If he stands out, he does so with some more or less conscious hope that his government may in time come to think as he does; whereas, in standing out against a foreign government, no such hope is necessary.  This group instinct, however it may have arisen, is what constitutes a nation, and what makes it important that the boundaries of nations should also be the boundaries of states.

National sentiment is a fact, and should be taken account of by institutions.  When it is ignored, it is intensified and becomes a source of strife.  It can only be rendered harmless by being given free play, so long as it is not predatory.  But it is not, in itself, a good or admirable feeling.  There is nothing rational and nothing desirable in a limitation of sympathy which confines it to a fragment of the human race.  Diversities of manners and customs and traditions are, on the whole, a good thing, since they enable different nations to produce different types of excellence.  But in national feeling there is always latent or explicit an element of hostility to foreigners.  National feeling, as we know it, could not exist in a nation which was wholly free from external pressure of a hostile kind.

And group feeling produces a limited and often harmful kind of morality.  Men come to identify the good with what serves the interests of their own group, and the bad with what works against those interests, even if it should happen to be in the interests of mankind as a whole.  This group morality is very much in evidence during war, and is taken for granted in men’s ordinary thought.  Although almost all Englishmen consider the defeat of Germany desirable for the good of the world, yet nevertheless most of them honor a German for fighting for his country, because it has not occurred to them that his actions ought to be guided by a morality higher than that of the group.