Oceania was at war with Eurasia: therefore Oceania had always been at war with Eurasia.

Since about that time, war had been literally continuous, though strictly speaking it had not always been the same war. For several months during his childhood there had been confused street fighting in London itself, some of which he remembered vividly. But to trace out the history of the whole period, to say who was fighting whom at any given moment, would have been utterly impossible, since no written record, and no spoken word, ever made mention of any other alignment than the existing one. At this moment, for example, in 1984 (if it was 1984), Oceania was at war with Eurasia and in alliance with Eastasia. In no public or private utterance was it ever admitted that the three powers had at any time been grouped along different lines. Actually, as Winston well knew, it was only four years since Oceania had been at war with Eastasia and in alliance with Eurasia. But that was merely a piece of furtive knowledge which he happened to possess because his memory was not satisfactorily under control. Officially the change of partners had never happened. Oceania was at war with Eurasia: therefore Oceania had always been at war with Eurasia. The enemy of the moment always represented absolute evil, and it followed that any past or future agreement with him was impossible. --George Orwell, 1984, via B.Ph.D.