200 years from now, I want their children's children's children's children to cower and cringe in fear whenever they hear the sounds of jet engines overhead because their legends tell of fire from the sky.
I want them to hide in dark caves and holes in the earth, shivering with terror whenever they hear the roar of diesel engines because the tales of their ancestors talk about metal monsters crawling over the earth, spitting death and destruction.
I want their mothers to be able to admonish them with "If you don't behave, the Pale Destroyers will come for you", and that will be enough to reduce them to quivering obesience.
I want the annihilation to be so complete that their mythology will tell them of the day of judgment when the stern gods from across the sea .. the powerful 'Mericans .. destroyed their forefathers' wickedness.
Apply the hammer often enough and even the toughest people will crack. We have no problems with the Apache and the Souix these days simply because this IS the way we handled the situation then. We did the same to Nazi Germany and Imperial Japan and that worked as well. We beat on them and their culture until it cracked and surrendered.
Works for me.