The secession of South Sudan marks a significant milestone in the political evolution of the African continent. The new state has no separate colonial heritage, and hence no recognised boundary, and has been formed as the result of a struggle for independence waged against the government of an independent state. International law on the subject of secession has been highly ambiguous and despite vigorous debate since the early 1990s, little progress has been made for the guidance of separatist movements or the international community in the resolution of such conflicts. The basic 'just-cause' motive for secession and an agreed constitutional means of attaining it were effective in the case of South Sudan, but only after a long period of civil war, which eventually reached stalemate. The inter-governmental cooperation necessary to effect the process of partition may carry over after independence, providing a better future for all in two states than had been possible in a single entity.