The three power blocks in Orwall’s world were always in a state of war. Here the main aim was to consume resources, materials and lives, as fast as possible. It was also one of the few feilds that progress was allowed to make.
The quote refers to the scence were Winston Smith has to aknowledge the control the Inner party has over history. It is how they decide events are recorded or analysed. It doesn’t matter what you know. In fact they are taught from an early age to doubt what they see and experience. They will be told what has “actually” happened. Sound familiar?