The Forever War by Joe Haldeman
The standard reading of *The Forever War* as Vietnam-allegory-in-space misses the stranger engine underneath. Mandella doesn't suffer because war is hell — he suffers because the relativistic return keeps delivering him to a civilization that has already metabolized his sacrifice and moved on. The war isn't the point. The lag is. Haldeman accidentally wrote the first novel about policy latency: the gap between the moment a decision is made and the moment its consequences arrive, by which time the decision-makers are dead or unrecognizable. Every veteran comes home to a country that isn't the one that sent them, but Haldeman literalizes this so brutally that it becomes a prediction rather than a metaphor. We are all now living in Mandella's problem — governing through instruments whose effects land in a future we can't model, for constituents who won't exist yet. The Forever War is less a novel about 1974 than a leaked memo from 2040: the age when every policy is a collapsar jump, and nobody knows where it comes out.