According to 1984, a hierarchical society is only possible on the foundation of....1984>BOOK 2> CHAPTER 9> BOOK OF THE BROTHERHOOD>CHAPTER 3:WAR IS...

According to the book, the basic motive for war at that
point in history is to maintain the artificial scarcity that dictates a wealthy elite
and a poor populace.  The fear is that without that scarcity, the rise of the rest of
the population to a life of relative comfort will allow them to understand that there is
no need for this hierarchical society and they will reject it by whatever means
necessary.  Because of this, a war in which surplus materials are used up and destroyed
becomes an absolute necessity for those wishing to maintain that privileged
elite.