There’s a lot to debate about Starship Troopers. But a reading of it as “fascistic” seems really strange. He portrays a society that has constitutional government; that has the franchise, and takes it really seriously, to the point of guaranteeing that anyone, even a blind paraplegic, can perform some kind of federal service and earn the right to vote; that does not practice conscription (was there ever a fascist society that had a volunteer military?); that in fact takes the avoidance of conscription so far that you can be given orders for a combat mission, decide you don’t want to accept it, and resign from the armed forces on the spot, with no penalty except that you never are allowed to vote; that has no elite officer corps but requires every officer to have started out at the bottom—in fact if you want to be high command you have to do that twice, once in the army and once in the navy. I don’t think any of that looks like fascism, and calling it that is only explainable if you suppose that any admiration for the military is “fascist”—and such admiration can be found in societies as varied as ancient Athens, both sides in the American Civil War, and the major Communist states of the twentieth century. If you call all of those “fascism” then I think it deprives the word of any possible meaning
What Heinlein is trying to get at is the basic Platonic dilemma of “Who will watch the watchmen?” Aristotle says that the good political systems, whether rule by a just king or by the vote of the people, treat political power not as something you own and use for your own gain, but as something you hold in trust for the whole people and use in their best interest. But how do you ensure this? Heinlein suggests that one way is to limit political power—the vote—to those and only those who have already shown that they care about the welfare of their society, sufficiently to put their own lives at risk to protect it. And that may not be a sufficient solution, but it’s an important question, and a problem that we are a long way from having solved.