  It is useful to distinguish secession from other ways in which “separation” or “state-breaking” can occur. In what might be called secession in the classic sense, a group in a portion of the territory of a state attempt to create a new state there; secessionists attempt to exit, leaving behind the original state in reduced form. Second, there is irredentist secession, wherein the attempt is not to create a new state, but to merge the seceding territory with a neighboring state. This typically occurs when the majority in the seceding area are of the same ethno-nationality as that which is predominant in the neighboring state. A third case, exemplified by the dissolution of Czechoslovakia, occurs when there is agreement between the populations or at least the leaders of two regions (which together comprise the whole territory of the state), to split the state into two new states. A fourth case is that of externally imposed partition of an existing state into two or more new states. In the past partition usually occurred when a deal was struck between two powerful neighboring states at the expense of the state that was partitioned, as with the partitioning of Poland between Nazi Germany and the Soviet Union. At present, externally imposed partition is more likely to be considered as a last resort for dealing with intractable ethno-national conflict within a state. In what follows, the focus is on secession in the classical sense, but with some attention also to irredentist secession.