From Notes on Nationalism, 1945:
A nationalist is one who thinks solely, or mainly, in terms of competitive prestige. He may be a positive or a negative nationalist – that is, he may use his mental energy either in boosting or in denigrating – but at any rate his thoughts always turn on victories, defeats, triumphs and humiliations. He sees history, especially contemporary history, as the endless rise and decline of great power units, and every event that happens seems to him a demonstration that his own side is on the up-grade and some hated rival is on the down-grade. But finally, it is important not to confuse nationalism with mere worship of success. The nationalist does not go on the principle of simply ganging up with the strongest side. On the contrary, having picked his side, he persuades himself that it is the strongest, and is able to stick to his belief even when the facts are overwhelmingly against him. Nationalism is power hunger tempered by self-deception. Every nationalist is capable of the most flagrant dishonesty, but he is also – since he is conscious of serving something bigger than himself – unshakeably certain of being in the right.
And this analysis of what he means in the case of Europe in the 1940s:
Now that I have given this lengthy definition, I think it will be admitted that the habit of mind I am talking about is widespread among the English intelligentsia, and more widespread there than among the mass of the people. For those who feel deeply about contemporary politics, certain topics have become so infected by considerations of prestige that a genuinely rational approach to them is almost impossible. Out of the hundreds of examples that one might choose, take this question: Which of the three great allies, the U.S.S.R., Britain and the U.S.A., has contributed most to the defeat of Germany? In theory it should be possible to give a reasoned and perhaps even a conclusive answer to this question. In practice, however, the necessary calculations cannot be made, because anyone likely to bother his head about such a question would inevitably see it in terms of competitive prestige. He would therefore start by deciding in favour of Russia, Britain or America as the case might be, and only after this would begin searching for arguments that seemed to support his case. And there are whole strings of kindred questions to which you can only get an honest answer from someone who is indifferent to the whole subject involved, and whose opinion on it is probably worthless in any case. Hence, partly, the remarkable failure in our time of political and military prediction. It is curious to reflect that out of all the ‘experts’ of all the schools, there was not a single one who was able to foresee so likely an event as the Russo-German Pact of 1939. And when news of the Pact broke, the most wildly divergent explanations were of it were given, and predictions were made which were falsified almost immediately, being based in nearly every case not on a study of probabilities but on a desire to make the U.S.S.R. seem good or bad, strong or weak. Political or military commentators, like astrologers, can survive almost any mistake, because their more devoted followers do not look to them for an appraisal of the facts but for the stimulation of nationalistic loyalties. And aesthetic judgements, especially literary judgements, are often corrupted in the same way as political ones. It would be difficult for an Indian nationalist to enjoy reading Kipling or for a Conservative to see merit in Mayakovsky, and there is always a temptation to claim that any book whose tendency one disagrees with must be a bad book from a literary point of view. People of strongly nationalistic outlook often perform this sleight of hand without being conscious of dishonesty.