The novel Semper Fi takes place in the year before the attack on Pearl Harbor and follows through the very early days of the war. Social issues, then, are typical of late prewar attitudes. For example, the main character, Kenneth "Killer" McCoy, is stationed in the Marine Corps in China in late 1940. Attitudes toward Chinese and Japanese, as well as toward other Europeans living in China, are shown through McCoy's eyes, particularly the atmosphere of antagonism evident in China before the beginning of the war.

Smaller social commentary and social vignettes are also shown, such a glimpse at the world of the very wealthy in the form of the Pickering and Foster families.