Low-level plague on a planet with a high-level replicant center. The population will never go away entirely; it will exist for all time in an endless cycle of born->suffer->die. Build a shipyard on the planet and force them to continue building warships for you. Station a large garrison of troops on the planet permanently.
Don't _let_ them die.
No, I wouldn't do something like this. though I'm considering the "throw them into a black hole" option in one of my games right now, depending on how the diplomacy swings.
Re: List Horrible Ways To Eliminate Populations
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