Science fiction and the United States military often inhabit the same imaginative space. Weapons technology has taken inspiration from science fiction, from the bazooka and the atomic bomb to weaponized lasers and drones. Star-spangled superheroes sold war bonds in comic books sent to GIs during World War II, and adorned the noses of bombers. The same superheroes now appear in big-budget movies made with military assistance, fighting evil in today's war zones. A missile shield of laser satellites--dreamed up by writers and embraced by the high command--is partially credited with ending...