*Some Spoilers Below*
The cover blurb on the copy I was reading referred to it as the science fiction Catch-22. While The Forever War has some of the same attitudes as Catch-22, what kept popping up in my head was how much this was a post-Vietnam response to Starship Troopers. On doing the barest of research, it appears Haldeman was wounded in combat in Vietnam, and that perspective is definitely in this science fiction book. In particular, what happens when you come home.
Like Starship Troopers, combat in space takes place using exosuits. In The Forever War, however, there is much more emphasis placed on how quickly and arbitrarily your suit could kill you. While I think it's acknowledged in Starship Troopers, (it's been a long time since I've read it), there is a good portion of this book dedicated to soldiers dying in training, senselessly, in order to get them ready for further senseless deaths out there. It's not as absurd as in Catch-22. In fact, it rings scarily realistic.
There is no heroic narrative here. And absolutely no sense that anyone survives due to their skill as a soldier. It doesn't matter. War doesn't care. You can do things right and die, and you could do things wrong and get through. Or still get killed. It's brutal and short, and one of the times the main character goes into combat, he's cut down in the first thirty seconds, before he can do a single damned thing. There was nothing he could have done that would have changed that, nothing he did wrong. Nothing he did right. War doesn't care, it doesn't conform to narrative expectations, and the likeable are not killed to make a point and light a fire under a main character's ass. They're just dead.
That's the moral universe we're operating in, and rings as hollow in fiction as it does in real life. No wonder we paper it over so often with stories of heroic survival and righteous combat.
The other main theme of the book is how the world goes on without you, and the culture shock of returning. This is heightened by relativity, in The Forever War, as the main character goes through ten years of war that span over a one thousand years on Earth. When he gets back after his first hitch, the world is irrevocably changed. It is more crowded, resources more strained, mass unemployment, and mechanization.
Sexuality has also changed, and that's an interesting section of the book. Haldeman's book theorizes that sexuality is largely the result of cultural conditioning, but no less strong for that. The main character, who enters the army when heterosexuality is the norm, is somewhat startled to find 500 years in, that due to population pressures on Earth and regulations on having children, homosexuality is now almost universal. It's the main character who is the freak, as all his new recruits regard him with some distaste.
In true post-Vietnam style, at the end of the book, we find out what started the war. And it's a kick in the gut. Haldeman does a really remarkable job in this book of the absurdities of war, but even more is focused on the petty and large cruelties, a world where the military doesn't qualify you for citizenship. Instead, it comes up with stupid ways to handle problems, disregards people, and sends them to be killed. As a rebuttal to Starship Trooper, it's quite brilliant.
I read this book as part of an attempt to read all the Hugo Nominees