Scientific interest in issues concerning federalism, which implies determining the difference between a confederation (a union of confederal states) and a federation (a federal state comprising federal entities) seems to have disappeared after the dissolution of the Socialist Federal Republic of Yugoslavia in 1992, the country which had existed in the period from 1945 to 1992 under different names: the Democratic Federal Yugoslavia (DFY), the Federal Peoples’ Republic of Yugoslavia (FPRY), and finally the Socialist Federal Republic of Yugoslavia (SFRY). Although a number of other confederations or federations (notably, the Soviet Union and Czechoslovakia) ceased to exist in the 20th century, history bears witness of the establishment of two important associations of states: the United Nations Organisation (UN) and the European Union (EU). They are highly significant for Serbia, which is a member state of the UN and cherishes close cooperation with the EU. However, the dissolution of the SFRY has not resolved some important issues among its former member states. The basic postulate of these problems is the fact that the Federal Peoples’ Republic of Yugoslavia (FPRY as “the second Yugoslavia”) is not the successor state of the Kingdom of Yugoslavia (“the first Yugoslavia”) because “the first Yugoslavia” was never dissolved, i.e. its international personality did not cease to exist; namely, the “second Yugoslavia” is only the continuator state (ensuring the continuity of the state in the territory of its predecessor), just as the Kingdom of Yugoslavia was the continuator state rather than the successor state of the Kingdom of Serbia. Hence, the problem comes down to the identity of legal subjects.
The essential difference between a confederation and a federation are as follows: 1) confederation member states may autonomously decide whether they would act independently abroad (e.g. to maintain diplomatic relations, to conclude international agreements, etc.); on the other hand, federal entities (members of a federation) do not have such an option, or they may possibly be given such an option (to an extend which is considered relevant) by the central (federal) government; 2) the internal borders between confederation member states may be changed only by international treaties adopted at an international conference, whereas the internal borders between federal entities may be unilaterally established and changed by the central government; 3) confederation member states, in principle, have the secession right (ius secessionis) to withdraw from the confederation, whereas federal entities have no such right.
It should be noted that a confederation, as a rule, has a capacity of legal personality in international law, just as its individual members. Yet, the difference between the internal state law and public international law is quite relative. Namely, as noted by Toma Živanović, international law (both private and public) is governed by collision norms. While the essence of private international law is conflict resolution involving subjective private rights and obligations arising from the internal law of different states, the essence of public international law is resolution of conflicts between different sovereign states.
The basic difference between a confederation and a federation is that each confederation member state is the holder of supreme power (sovereignty), whereas the federal units in a federal state have no such power, given the fact that sovereignty is exclusively vested in the federation (federal state). The supreme power is a de facto matter; it implies the capacity to maintain public order in a specific territory. Relying on the comparative research of different confederations and federations, the author comes to a conclusion that the “second Yugoslavia” (FPRY) was actually a confederation (despite its official title). However, this conclusion raises the question of borders between its former member states, particularly considering that these (FPRY) borders were not established by any international treaty. Given the fact that there is legal continuity between the Kingdom of Serbia, the “First Yugoslavia” (Kingdom of Yugoslavia) and the “Second Yugoslavia” (FPRY), the solution must be sought in the process of restitution, which implies a return to a prior state of affairs that existed before the creation of the (first) Yugoslav state.