What are the motifs in Starship Troopers by Robert A. Heinlein?

History is a recurring idea in the story. Society, in the future age in which Starship Troopers is set, has a high appreciation and keen knowledge of history. This appreciation and knowledge is likely higher than in the 1950’s, when the novel is written, and certainly higher than in modern America. High schools, except those in the most remote areas of the earth, must offer a course in History and Moral Philosophy (H&MP). It is not graded; but all must attend. Juan Rico’s father sees it as a thinly veiled attempt at recruiting for the military.