From Kurdistan to Somaliland, Xinjiang to South Yemen, all secessionist movements hope to secure newly independent states of their own. Most will not prevail. The existing scholarly wisdom provides one explanation for success, based on authority and control within the nascent states. With the aid of an expansive new dataset and detailed case studies, this book provides an alternative account. It argues that the strongest members of the international community have a decisive influence over whether today's secessionists become countries tomorrow and that, most often, their support is conditioned on parochial political considerations.