The formation of new nations often has dramatic consequences for migration flows. As we approach the end of the twentieth century we can anticipate the creation of an additional 140 new nation states since the founding of the United Nations in 1945. Many recognized states, as Zolberg et al. (1989: 233) have maintained, have been created through constitutional, peaceful means. However, where things go wrong, they often go terribly wrong (Zolberg 1983). The negative case normally arises when the three cognate processes of decolonization, the implosion of empire and the demands for self-determination do not entirely match. Beyond that generalization there are a host of particularities which cannot all be specified in detail here. Often a weakened empire still has sufficient resilience to negotiate an ordered withdrawal. (This happened, for example, in many countries of the British Commonwealth and in French West Africa and Equatorial Africa.) Sometimes the process of implosion has gone too far – the circumstance that confronted the Soviet Union after 1989. Those pressing for decolonization or statehood can adopt a range of peaceful or violent means in pursuit of their objective. In a number of cases there is a complicating factor arising from the presence of a significant numbers of settlers from the former metropolis. (Where the movement for self-determination is strong or violent, this can result in the repatriation of the settlers, as explained in Part 10.) Again, dominant and subordinate minorities may not agree about the shape of the new state or which national, religious or ethnic groups form a legitimate part of it.