I think the movie quite straightforwardly expressed most of the misunderstandings associated with the book, and ignored the actual book. I had heard the movie was about 80% complete before the title was licensed and it became Starship Troopers rather than a random dystopia. Learning that the director never bothered to read the book cements it for me.
The book is a coming of age story set in a society where those who have a history of being able to put “all of us” ahead of “me” are in charge. Federal service is by design individually dangerous: service consists of accepting personal risk to further humanity. Jobs without risk are not Federal service; they are just jobs. Jobs with risk but without furthering humanity are also not Federal service: they are just jobs. Laboring in the terraforming of Venus is a service job. Manufacturing machinery for the terraforming of Venus is not. The rewards of citizenship are few and non-monetary: the right to vote, presumably the right to be elected to office, and the opportunity to apply for the few “reserved” government positions (policeman, History and Moral Philosophy teacher). There is no hint that non-citizenship has any implication as to what are typically considered “rights” other than those. Economic activity, owning property, having employees, speaking one’s opinion, and so forth are all unimpacted. There are passages that make it clear that citizenship is widely regarded as fundamentally irrelevant: certainly it is not considered any sort of superior state.
It is this setting that makes the book is so intensely disliked: the everyman who has not demonstrated putting “all of us” ahead of “me” is not allowed to make decisions that affect “all of us.” This incenses those of all political stripes who want to tell everyone else how to live their lives. And yet this is possibly the most creative reconciliation yet of the need for government with the philosophy of Libertarianism. Humanity is one of the most social creatures on the planet, gathering in the millions: we call the infrastructure for these gatherings “government,” and it appears we need it. If we must have government—and it appears we must—what selection criteria is “optimal” for the humans who compose it? Starship Troopers, the book, proposes a demonstrated history of valuing “all of us” over “me.” In the book, it works: and this is the only reason for its endurance given.
Rico, the protagonist, does not sign up for the military. He signs up for Federal service and, for what are basically romantic reasons, chooses the military rather than other work—and is almost rejected for it. The rest of the book, unsurprisingly, follows Rico through several vignettes of military service. The military is a setting for the various growth experiences Rico experiences, not the subject. Nor, in the book’s society, is staying in Federal service compulsory: at least in the infantry branch the book describes, declining to further serve gets you out without penalty (other than forfeiting the privileges of having successfully served). It is only half-way through the book that Rico eventually self-identifies as a member of the military, when he “goes career.”
The military is treated respectfully in the book, but the limits of military power are also explored. The purpose of war has been given as “to destroy the enemy’s will and ability to resist;” the book gives the purpose of the military as using deliberate, focused, measured, precisely applied violence to this end. The book is quite open that force cannot change attitudes or beliefs: force can only change behavior, and that only temporarily. There are those who propose that wholesale slaughter might have its place in war; but this is neither typified nor glorified by the book.
In summary, the Starship Troopers book and Starship Troopers movie have just about nothing to do with one another. The movie is “facism is bad!” The book is “growing up is good” along with a “what if government ran this way?”