The inter-relationship between fiction and imagination are critical in the defining the Vietnam war in O'Brien's book. War is real although the soldiers are fictional. The realities of war and its devastating effects are clearly defined from imaginations of the reader as depicted by the imaginary characters. O'Brien purportedly asserts a piece of information to be factual and later confesses to it being fictitious is evidence that he is consciously aware of the use of both fact and fiction in writing his book.
While advocating that stories can bring dead people back to life the dimensions of imagination and reality are further realized. In context dead people can only be imagined to be alive and live people will factually continue to exist as alive or dead people are actually dead and will factually remain to be dead. O'Brien continually reaffirms to the reader about the authenticity of the story of Rat Kiley slowly killing a baby water buffalo and despite the fact that the reader knows pretty well that it is fictional they actually accept it as factual.
The existence of social codes and contracts in the platoons become arbitrary. Thieves for example are punished by others to create fear in others in committing the same bad unacceptable acts in society. The relationship between Jensen and Strunk and the social contract they make is much evidence of the increasing social pressure caused by the ravages of war.
Most of the social pressure in the book is evident in the quests to prove one's bravery. Another good example of the social pressure is in the intensity of war and honor is revealed when in chapter eight Curt Lemon has a tooth pulled out just to prove he is not afraid of the dentist. In chapter four Tim chooses to go to war to be seen as brave despite his fear and shame. Tim also feels the guilt and shame of killing a young man and sees nothing brave in the act. Most of the men join the army out of a need to fulfil their social obligation to society. Norman Bowker joined the war out of popular cultural pressure and the need to impress his father and the society with medals. He succeeds in getting all the medals except one and the social pressure continues to haunt him even after returning from the war evidenced in the need to be a good citizen and hold down a job and have relationships.
The story on the Rainy River shows evidence of social pressure as he receives his draft notice and does not want to fight in a war he does not believe to be just. His peers have a motivating factor in his decision about the war and O'Brien has fear of being ashamed before his peers. The decisions that O'Brien makes to fight in the war and not to flee into Canada arise from the social influence his family and community have on him and what they would think of him if he does not fight in the war.