Military science fiction, a genre probably started by Starship Troopers, which I have yet to read (though I have seen the film, and its fairly predictable sequel- Hero of the Federation). I would recommend The Forever War by Joe Haldeman, effectively a response to Starship Troopers. The two books characterise the two sides of the genre, Heinlein’s allegedly glorifying conflict and Haldeman’s highlighting the sacrifice of the ordinary soldier and their alienation from the people they are supposedly fighting for in an ultimately pointless war.
Baen books publish a lot of contemporary military science fiction, mostly of the more militaristic, right-leaning type. I’ve read a few of them in the last couple of months, from the library or a big bag of battered editions I was given. Carrying on the trend of getting them for free, I’ve just downloaded a few novels from their free library. They’re all good, no-nonsense reads that aim primarily to provide entertainment without breaking much new ground. The occasional lecture on the greater merits of military service, duty and sacrifice tend to slide past without offending or disrupting the flow of the tale.
What I’m thinking of now is writing a few short pieces in the genre, subverting it a bit with my defeatist liberal outlook. The horror, futility and blowback of a poorly planned war entered into for the wrong reasons should provide a good backdrop.