In his first blog post in nearly a month, Charlie Stross opines on one of Heinlein’s most polarizing novels:
In the 1930s, Heinlein was a soft socialist — he was considered sufficiently left wing and “unreliable” that he was not recalled for active duty in the US Navy during the Second World War. After he married Virginia Gerstenfeld, his third and last wife, his views gradually shifted to the right — however he tended towards the libertarian right rather than the religious/paleoconservative right. (These distinctions do not mean in 2021 what they might have meant in 1971; today’s libertarian/neo-nazi nexus has mostly emerged in the 21st century, and Heinlein was a vehement opponent of Nazism.) So the surface picture is your stereotype of a socially liberal centrist/soft leftist who moved to the right as he grew older.
But to muddy the waters, Heinlein was always happy to pick up a bonkers ideological shibboleth and run with it in his fiction. He was sufficiently flexible to write from the first person viewpoint of unreliable/misguided narrators, to juxtapose their beliefs against a background that highlighted their weaknesses, and even to end the story with the narrator — but not the reader — unaware of this.
In Starship Troopers Heinlein was again playing unreliable narrator games. On the surface, ST appears to be a war novel loosely based on WW2 (“bugs” are Nazis; “skinnies” are either Italian or Japanese Axis forces), but each element of the subtext relates to the ideological awakening of his protagonist, everyman Johnny Rico (note: not many white American SF writers would have picked a Filipino hero for a novel in the 1950s). And the moral impetus is a discussion of how to exist in a universe populated by existential threats with which peaceful coexistence is impossible. The political framework Heinlein dreamed up for his human population — voting rights as a quid pro quo for military (or civilian public) service — isn’t that far from the early Roman Republic, although in Rico’s eyes it’s presented as something new, a post-war settlement. Heinlein, as opposed to his protagonist, is demonstrating it as a solution to how to run a polity in a state of total war without losing democratic accountability. (Even his presentation of corporal and capital punishment is consistent with the early Roman Republic as a model.) The totalizing nature of the war in ST isn’t at odds with the Roman interpretation: Carthago delenda est, anyone?
It seems to me that using the Roman Republic as a model is exactly the sort of cheat that Heinlein would employ. But then Starship Troopers became the type specimen for an entire subgenre of SF, namely Military-SF. It’s not that MilSF wasn’t written prior to Starship Troopers: merely that ST was compellingly written by the standards of SF circa 1959. And it was published against the creeping onset of the US involvement in the Vietnam War, and the early days of the New Wave in SF, so it was wildly influential beyond its author’s expectations.
The annoying right wing Heinlein Mil-SF stans that came along in later decades — mostly from the 1970s onwards — embraced Starship Troopers as an idealized fascist utopia with the permanent war of All against All that is fundamental to fascist thought. In doing so they missed the point completely. It’s no accident that fascist movements from Mussolini onwards appropriated Roman iconography (such as the Fasces): insecure imperialists often claim legitimacy by claiming they’re restoring an imagined golden age of empire. Indeed, this was the common design language of the British Empire’s architecture, and just about every other European imperialist program of the past millennium. By picking the Roman Republic as a model for a beleagured polity, Heinlein plugged into the underlying mythos of western imperialism. But by doing so he inadvertently obscured the moral lesson he was trying to deliver.