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This article has been written by Disha Mohanty of National Law University and Judicial Academy, Assam. State succession under Public International Law is one of the most interesting aspects of International Law and very relevant in the current world situation. This article attempts to explain the concept of state succession, the theories behind it and the repercussions of it.


State succession refers to the merging of two or more States. It is different from government succession in the sense that in government succession there’s a change of government whereas in State succession the State loses control over its partial or whole territory. Art 2(1)(b) of the Vienna Convention on the succession of States in respect of treaties in 1978 defines the term State succession as ‘the replacement of one State by another in the responsibility for the international relations of territory’.

In essence, it deals with the succession of one state with another and the transfer of rights and obligations. This concept has assumed greater importance since World War II owing to its effects on the legal obligations of the States. 

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Circumstances of State Succession

State succession can arise in a number of defined circumstances, which mirror the ways in which political sovereignty may be acquired. They are: 

  • Decolonization of all or part of an existing territorial unit: This refers to situations where the nation partially or completely overcomes itself from the holding of a superior nation.
  • The dismemberment of an existing State: This refers to a situation when the territory of the predecessor State becomes the territory of two or more new States who take over it.
  • Secession: This refers to a situation where a part of the State decides to withdraw from the existing State.
  • Annexation: This refers to a situation where a State takes possession of another State.
  • Merger: This refers to the fusion of two or more free States into a single free State.

Types of State Succession 

In each of these cases, a once-recognized entity disappears in whole or in part to be succeeded by some other authority, thus precipitating problems of transmission of rights and obligations. There are two types of State succession and they are discussed below:

Universal Succession

This is also referred to as Total Succession. When the entire identity of the parent State is destroyed and the old territory takes up the identity of the successor State, it is known as Universal Succession. This can happen in cases of:

  • Merger
  • Annexation 
  • Subjugation

In certain cases of universal succession, the old State gets divided into multiple States. The dissolution of Czechoslovakia is an example of universal succession. The new States of the Czech Republic and Slovakia are both successor States. 

Partial Succession

Partial Succession occurs when a part of the territory of the State gets severed from the parent State. This severed part now becomes an independent State. This can occur when there is a civil war or a liberalization war. 

There are two important examples of partial succession.

  • One is the separation of Pakistan from India.
  • The other is the separation of Bangladesh from Pakistan.

The existing States continued with their legal obligations and duties while the new States got their own recognition and carried no rights or duties of the parent States.

Theories of State Succession

Universal Succession Theory

This is the oldest theory of succession propounded by Grotius, using the Roman analogy of succession on the death of any natural person. According to this theory, the rights and duties of the old State i.e., the predecessor State pass on to the new State i.e., the successor State upon succession without any exceptions and modifications. 

In fact, there are two justifications behind this theory. 

  1. First that the State and the Sovereign gain all their power from God and a mere change in Government shouldn’t cause any change in the powers. 
  2. Second, it is permanent and nothing can cause it to secede. 

The application of this theory can be seen in cases of fusion in the 20th century. The fusion of Syria and Egypt, Somali Land and Somalia, Tanganyika and Zanzibar are examples of this. However, this theory failed to get any attention from the majority of States from the world and has also been criticized by scholars from the world due to its Roman law analogy, a poor distinction between succession and internal change in governments, etc. 

Popular Continuity Theory

The Popular Continuity Theory can be described as another version of the Universal Succession theory that was propounded by Fiore and Fradier following the unification of the German and Italian nationals. According to this theory, the State has a 

  • Political personality: It basically refers to the rights and obligations of the State towards the government. 
  • Social personality: lt basically refers to the territory and the population of the State. 

Hence, upon succession, the political personality gets changed whereas the social personality remains intact. So, a State succession would not alter the rights and duties of the populace. 

However, this theory has not found its application in any country outside Europe and also has been criticised on the grounds that it functioned according to the municipal laws i.e, the local laws, which is why it was difficult to understand the effect of State succession using this theory.

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Organic Substitution Theory

According to this theory, the rights and duties of the State continue even after succession by another State. Von Gierke had published a paper in 1882 regarding The execution of rights and obligations of a social body after its dissolution. It was from here that Max Huber derived his organic substitution theory. Huber drew the analogy that the problem of State succession was similar to that of dissolution of a social institution.

The factual element of the people and the territory have an organic bond i.e., the bond between the people and elements of State and upon succession by a new sovereign, the organic bond remains intact and only the juridical element changes. It offers a new explanation to the continuity of rights and duties i.e., the substitution of a successor State in the personality of its predecessor State. But, just like the other theories, this theory too has had no practical application and has been criticized for the same.

Self Abnegation Theory

This theory was propounded in 1900 by Jellinek and is another version of the universal theory of continuity. According to Jellinek, the successor State agrees to observe the rules of international law and performs the obligations towards other States created under them. Although, this theory considers that the performance of the international obligation, is merely ‘moral duty’ of the successor State, but at the same time it gives the right to the other States, to insist upon the successor State to perform the existing obligation. If the successor State refuses to accept, the other States may even withhold its recognition or make the recognition conditional upon the acceptance of the predecessor’s commitment towards them. 

Negative Theory

This theory was developed during the mid-19th and early 20th centuries. After World War II, the jurists of the Soviet Nations started emphasizing on the right of self-determination and on giving complete freedom to the States to maintain their international relations. According to this theory, the successor State doesn’t absorb the personality of the predecessor State in its political and economic interests. 

Upon succession, the new State is completely free of the obligations of the predecessor State. The successor State does not exercise its jurisdiction over the territory in virtue of a transfer of power from its predecessor but it has acquired the possibility of expanding its own sovereignty.

Communist Theory 

According to the Communist Theory of State Succession, a successor State is burdened by the economic and political commitments of the predecessor. Thus, this comes as something completely contrary to the Negative Theory of State Succession and unlike the Negative Theory, it doesn’t free the successor State from the obligations of the predecessor State. 

The Successor State is bound to adhere to the commitments of the predecessor State. Political commitments involve peace, war and territorial treaties and agreements while economic commitments include any amount of money borrowed or lent. All these have to be fulfilled by the new State.

Rights and Duties arising out of State Succession 

The laws regarding State succession are still in a very nascent stage and keeps evolving with the changing times. As seen above, along with the territorial and power transfers, there are transfers with regard to duties too. This section gives a brief idea about the transfer and non-transfer of political as well as non-political rights and duties.

Political Rights and Duties

  • No succession takes place with regard to political rights and duties of the States. 
  • The peace treaties or the treaties of neutrality entered into by the previous State aren’t binding on the new State. 
  • But the only exception here is in case of human rights treaties since it would be desirable for the new State to adhere to such terms. 
  • Other than this, the new State would have to enter into new political treaties of its own.

Rights of Natives or Local Rights

  • Unlike the political rights and duties, the local rights of the people do not secede with the succession of the States. 
  • These rights refer to the rights such as property rights, land rights or rights relating to railways, roads, water etc. 
  • In cases like these, the succeeding States are bound by the duties, obligations and rights of the extinct State.  

Fiscal Debts (State or Public Debts)

  • These refer to the financial obligations or debts of the predecessor State. The successor State is bound to pay back the debts of the predecessor State.
  • This is because if the new State is enjoying the benefits of the loans, it becomes a moral obligation as well to pay back the money. 
  • Next, if there is a split in the State then the entire debt amount gets divided between the predecessor and successor State in accordance with the territory and population of each. 

Effect of State Succession on Treaties

The law on State succession with regard to treaties has for a long time been dominated by two principles in general:

  • One is the alleged principle of universal succession and 
  • The other is the tabula rasa approach i.e., clean State doctrine not granting State succession to treaties. 

While the former principal keeps in mind, the interests of third States regarding upholding or not upholding treaties, the latter favours a rather strict understanding of sovereignty i.e., functions only according to the interests of the successor and predecessor State. Neither of the two principles can, however, offer a practical solution for various scenarios where State succession takes place. Accordingly, under customary international law more nuanced solutions have been developed in the past or, at the least, are in the process of being formed.

The Vienna Convention on State Succession provides that:

  • In case of the border treaties, no such significant changes would be observed and the treaties would pass to the successor State.
  • This is done keeping in mind the greater interests of the International Community. Similarly, other forms of local treaties related to land, territory, etc. would also pass on to the successor State upon succession. 
  • Treaties relating to Human Rights are passed on to the successors with all their rights, duties and obligations. In the case of treaties relating to peace or neutrality, no succession takes place. 

Effect of State Succession on UN Membership 

When Pakistan was separated from India, it claimed itself to be a member of the United States since India was a member of the UN. The then Secretary-General of the UN had then brought up the following: 

  • From the perspective of International Law, the circumstance is one in which part of the State breaks off from the original State.
  • When Pakistan separated from India, there was no change in the status of India. India continued with all its treaties, rights and obligations.
  • On the other hand, Pakistan didn’t have any of those rights or obligations and of course, had lost the UN Membership. 
  • In International Law, the situation is similar to the separation of the Irish Free State from Britain, and Belgium from the Netherlands. In these cases, the portion which separated was considered a new State, and the remaining portion continued as an existing State with all the rights and duties which it had before. 

Thus, in the case of succession, the UN Membership doesn’t get transferred.


Given the current status of the law with regard to the idea of State succession, it can be very well inferred that the law needs a lot more evolution and clarity. Even though lately, it has been seen that there has been some consensus on certain levels and that succession doesn’t necessarily lead to disruption in all legal practices and methods there is a lot more work that needs to be done in this field.



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