Doctrinal overview of international legal status and regulations that may apply to the Caspian ‘sea’
It is quite clear that in the times of Soviet Union the problem of the international legal status of the Caspian was not so acute because the water basin was de facto a property of the USSR.11 With the new states emerging in the region it became progressively hard to solve trans-border and legal issues regarding the fishing, exploration of the shelf and seabed, exploitation of the water basins and energy resources. In that sense, there are some theories in legal doctrine as well, that differ based on the legal school of the country they originate from.
In Russian doctrine for example, there are views that legal status of the Caspian ‘sea’ have been defined by the scholars mostly in two categories: 1) mare clausum (enclosed sea) or 2) border lake. Thus, only depending on the categorization of the water basin either as enclosed sea or border lake the international legal status of the Caspian can be defined.  In line with that went the discussion in the Western doctrine that sought to differentiate between definitions of ‘border lake’ and ‘enclosed sea’ in regard to the Caspian.
In Iranian doctrine though, the general view went into the other direction. Using the geographical factor to justify the view, Iranian scholars believe that Caspian ‘sea’ have always had a sui generis status. Basically such view equalizes the water basin to the condominium. They seem to suggest that geographical unity of the territory of the Caspian is making it impossible to be shared and thus it becomes common property. One scholar relates this to the ‘spirit and letter’ of the agreements between Iran and USSR that “legally define the Caspian sea as condominium”.
Moreover, in Western doctrine the thought is deepening with the vies that international legal status of the Caspian is not dependent on the principles of jus cogens, meaning that the norms of international law that must be followed and enforced universally are not in place yet for that situation. That means that littoral states are free in defining such legal status by any treaty that they may have between them. It seems that the current status is seen as lacking basis and inadequate in the face of new realities and should be changed in accordance with the principle cessante ratione legis, lex ipsa cessat. Thus, the only solid legal status for Caspian ‘sea’ is the status that would allow equal opportunities for the development of all littoral states and the fair exploitation of natural resources. Such status maybe achieved only by the expression of the free will of all the littoral states.
However, despite the fact that the free will of the states will be decisive for the international legal status of Caspian ‘sea’, it seems fair and logical to take a look at and analyze the legal categories of ‘labeling’ this water basin as enclosed sea, border lake or condominium in order to understand which of them is more applicable and in line with international law doctrine.
When it comes to categorizing the Caspian as a sea, outside and surfaced factors seem very attractive. Even more so because such a notion have been reflected in the name of water basin - ‘Caspian Sea’. However, when it comes to international law and generally to science, the situation may not be as clear and straightforward as it may seem.
It has to be taken into account that historical tradition of naming the water basin a ‘sea’ cannot be the starting point in defining the legal status of the Caspian. Equally, its size and depth cannot be objective criteria as well due to the fact that international legal acts do not count them as such in classification of the seas and lakes. Moreover, there are no universal legal criteria that allow for such classification at all. In most of the cases geographical factors, such as access to the oceans and salt levels as well as the general practice play bigger role.
Nonetheless, there are arguments in doctrine that classify the Caspian as a sea. The straightforward notion of such classification can be found in the early Soviet publications that imply that Caspian ‘sea’ is geographically closed and surrounded by the territories of two states (Russia and Iran) and viewed as Soviet-Iranian sea. That notion has followed on through the whole period of Soviet doctrine and was supported by the counterparts in Iran even in early 1990s, for example in the works of Moghtader, that claimed that the Caspian is a largest enclosed sea in the world.
Similar notions were also supported by geologists that have viewed the Caspian as a leftover of the larger sea that have covered the present territory of Central Asia in ancient times several thousand years ago. Authors from Kazakhstan, for example Salimgerey, also refer to the Caspian as the ‘sea’ putting forward the arguments of some western and Russian scholars that call it ‘continental sea’, ‘enclosed sea’ or even ‘deep internal sea’.
What legal implications such a definition may lead to, is that if the Caspian is indeed the ‘sea’ then it will fall under the legal regime of the UN Convention of 1982 on the Law of the Sea (hereinafter the Convention) and specifically its Part IX “Enclosed or semi-enclosed seas” article 122 by definition. The legal status of the Caspian then will be determined by the article 123 of the Convention in due course of the cooperation of the littoral states while fulfilling their obligations under the treaty. What is more important is that it would mean all the appropriate international legal status under the Convention attributed to the seas. For example, 12-mile territorial waters, 200-mile continental shelf and exclusive economic zones. However, due to the fact that the Caspian’s breadth is not more than 200 miles, there maybe possibilities of determining the median line for the delimitation.
There are also arguments in favor of the theory that the Caspian should be a condominium. What is understood generally by such a notion is the international legal regime where two or more states exercise equal sovereign rights in political and judicial sphere over certain territory. Such notion fits into the logic that the Caspian problem is foremost the territorial dilemma.
Generally in the international law doctrine mainstream view is that when it comes to the territory that is administrated jointly by the exercise of sovereignty over land or water by two or more states, it is impossible to talk about the separation of sovereign rights. In accordance with the same view the condominium legal regime can be applied to deal with the problems between states over the bordering rivers and such. However, condominium is not commonly regulated by the norms of the international treaty law and mostly used as custom. To apply the regime of condominium to the given situation - the treaty between the parties should be concluded that would define the common sovereignty over territory, special administrative bodies, legal regime, etc.
In Western doctrine some believe that condominium is a regime of shared sovereignty in international relations. The main precedent of such a shared sovereignty over the enclosed water basin in the international law is the shared participation of Salvador, Honduras and Nicaragua in the Gulf of Fonseca. Thought condominiums more commonly reflect the will of the participating states, in case of the Gulf of Fonseca, condominium was established by the decision of the International Court of Justice. The reason for that was that this gulf was formerly under sovereignty of a single state - Spain, that used it as a single water basin. The Court found that it would not be wise to end this unique situation when the new states appeared on the map. The view thus is that the situation with the Gulf of Fonseca is very similar to the situation with the Caspian after the dissolution of the Soviet Union. The only difference being that the Caspian as a whole did not belong to a single state.
Russian doctrine has condominium theory followers as well, basing their view that such a regime was used in the past. Some say that there is a need to come back to previous Russian-Iranian agreements and that would lead to the political, territorial and environmental unity of the Caspian as the condominium zone would thus be established. The argument is that due to the regime in the Soviet times, Caspian ‘sea’ was a condominium with the exception of the 10-mile fishing zone. Such views are contrasted with other scholarly perception that the condominium regime was a formal facade for the third states, but have never been a de facto reality for USSR and Iran. 
It has to be pointed out that the condominium theory in regard of Caspian ‘sea’ is the least popular among scholars. On the over hand, the view that Caspian ‘sea’ is actually a border lake, with some interesting precedents and practice in international relations and specific norms in international law, can be pointed out as the most popular.
Moreover, such a point of view became popular even in the Iranian doctrine. For example, Afrasiabi in his work points out that the whole dispute over the Caspian lies in the question of whether the international norms of law of the sea will be applicable to the water basin or if the littoral states will be forced to negotiate on the status of the Caspian as a lake and dividing it into sovereign zones between the five parties. Author suggests that the status of the ‘lake’ would be a justified one. The same logic can be found in works of another Iranian author that acknowledges that the term ‘Caspian sea’ can be deceiving linguistically, due to the historical practice of calling this water basin a ‘sea’. However from the legal point of view the Caspian cannot be considered a ‘sea’. Geographical overview provided by yet another Iranian author, for example, views the Caspian as an intercontinental water basin that is not linked with any ocean and can be classified only as a lake. Such classification is a key toward the ultimate understanding of the legal status of the Caspian.
The similar views can be found in the Western doctrine as well. Some scholars argued that the Caspian is border lake bound between USSR and
Iran as a water basin that does not have an access to the world ocean. Moreover, as early as in 1960s the view that the Caspian was wrongfully classified as USSR’s enclosed sea when it is the largest border lake in the world can be found in British juridical literature. The same goes to the French doctrine where the views were quite similar pointing out that Caspian ‘sea’ as well as Aral ‘sea’ are in reality large lakes that fall under national jurisdictions. Thus, as they used to belong to the USSR and Iran their waters have been granted border status. Scholars find it surprising that despite the size, resources and ancient history of these border lakes they are one of the least regulated.
Moreover, when it comes to the legal consequences of the (rightful) classification of the Caspian as a lake, the classical American doctrine of international law (that has such an experience as Great Lakes between US and Canada) can be ultimately cited. It is believed that when a lake or an enclosed sea is surrounded by the territories of two or more states, it can be vied as belonging to those states in equal proportions if they choose to agree to that. Basically such view tells us that when it comes to the border lake the will of the states will determine its final legal status. The states may chose to keep it in common property or they can choose to divide its waters to open and territorial, with limitations or exclusivity of rights of third parties on shipping, fishing or other types of maritime regimes. Unlike the status of the sea, which falls under strict norms of international law, border lake can be divided by the will of littoral states into the zones of functional jurisdiction in maximum capacity - including seabed, waters, subsoil and airspace.
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