What are the motifs in The Forever War by Joe Haldeman?

Pacifism is actually a motif here. The position of the author is patently anti-militaristic in that there is not a single mention of anything positive coming from UNEF, the war, or the government. In fact, even the enemy is portrayed as the peaceful victim of a vicious attack from Earth based strictly on economic need. The two battles in which Mandella directly participates are graphically illustrated as bloodbaths executed by pawn-like soldiers who also are victims of a powerful and unstoppable chain of command. Mandella's actions in relation to violence throughout the novel demonstrate a belief in pacifism, specifically anti-militarism. Violence in self-defense and subjective justice is depicted as acceptable by his use of a gun to kill a gang-rapist and commune raiders.