Also for those who might be mislead by the title, Orwell is discussing something much broader here:
>But here I must repeat what I said above, that I am only using the word ‘nationalism’ for lack of a better. Nationalism, in the extended sense in which I am using the word, includes such movements and tendencies as Communism, political Catholicism, Zionism, Antisemitism, Trotskyism and Pacifism. It does not necessarily mean loyalty to a government or a country, still less to one’s own country, and it is not even strictly necessary that the units in which it deals should actually exist. To name a few obvious examples, Jewry, Islam, Christendom, the Proletariat and the White Race are all of them objects of passionate nationalistic feeling: but their existence can be seriously questioned, and there is no definition of any one of them that would be universally accepted.