Much of the early criticism of colonial genocide and genocidal practices elsewhere came from Marxists such as August Bebel, Antonio Gramsci and Ho Chi Minh. The German Left were strong critics of the colonial policy that led to the genocide against the Nama and Herero peoples. When Marxist regimes came to power after the First and Second World Wars, they initiated population politics which were highly detrimental to historical ethnic communities. This has led to a serious crisis of legitimacy on the Left. Clearly, the legacy of debates of the early inter-nationalists is still relevant as we discuss genocide as both a historical and contemporary phenomenon, but it is also essential that we use the full range of new analytical approaches as well as the comparative approach to understand and even begin to prevent this phenomenon.