Nationalism is only a curse when it becomes narrow and fanatical. Like so many other things available to man, say, religion, it can easily lead men astray. Nationalism can lead people into thinking only of themselves, of their own struggles. of their own misery. It can also cause a nation to become suspicious and fearful of its neighbours. to look upon itself as superior, and to become aggressive. And it is when nationalism impels a state to become expansionist and seek domination over others that it becomes a positive curse and harmful internationally. Which of the following phrases most correctly suggests the central theme of the passage?