Let's not forget post-colonialization. Less explicit, still as effective in resource grubbing and divide-and-conquer.
From the people that lovingly prepared the best conflict zones for after they leave, such as India-Pakistan, Israel-Palestine, Ethiopia-Eritrea, Iran-Iraq, Nothern-Southern Cyprus etc.
That, and also being conditioned not to thing so and blame themselves. Works wonder for keeping them at bay.