- Quarantined World — The world is under a quarantine, and space travel to and from it is strictly forbidden. This may be enforced by massive ground batteries that burn any interlopers from the planet’s sky, or it may be that a neighboring world runs a persistent blockade.
- Revolutionaries — The world is convulsed by one or more bands of revolutionaries, with some nations perhaps in the grip of a current revolution. Most of these upheavals can be expected only to change the general flavor of problems in the polity, but the process of getting there usually produces a tremendous amount of suffering.