In normal or propitious circumstances, national loyalty is the peaceful form of life that exists among people who share a defined territory and endeavor to live under the laws of that territory together. National loyalty attaches us to a place, and to the people who share in its life. Destroying national loyalty would almost certainly bring about the return of loyalties based on creed and blood.
One of the outstanding features of nationalist political movements, the thing that almost always strikes observers about them, is their irritated or aroused character. And it is precisely this that strikes non-nationalists as signaling danger. Republican democracies should be characterized by deliberation. Conservatives distrust swells of passion. Liberals want an order of voluntary rights. But nationalist movements are teeming with powerful emotions: betrayal, anger, aggression.
Therefore, I contend, like a fever, nationalism can be curative or fatal. And, like fevers, it can come and go depending on the nation’s internal health or the external circumstances a nation finds itself in. Foreign aggression and the onset of war will reliably generate nationalist moods and responses. But cultural change can do it too. Maybe a national language falls into sharp and sudden decline under pressure from a more powerful lingua franca. Even something as simple or common as rapid urbanization can be felt to agitate upon a people’s loyalties, and may generate a cultural response for preserving certain rural traditions and folkways. And of course, sometimes nationalism is excited by the possibility of some new possession coming into view, the opportunity to recover or acquire territory or humiliate a historic rival. The variety of irritants explains the variety of nationalisms.