Acquisition of State Territory
Occupation
State territory is a fundamental element of statehood. International law provides rules regarding how States can acquire title to territory. Historically, several modes of acquisition were recognized, though some have been modified or become less relevant in modern international law (especially after the prohibition of the use of force).
Occupation is a mode of acquiring territory that is not under the sovereignty of any State.
Territory *res nullius*
Occupation applies only to territory that is *res nullius*, meaning territory belonging to no one. This includes newly discovered lands that have not been previously claimed by any State, or territory that has been legitimately abandoned by the previous sovereign.
Territory inhabited by indigenous populations without a recognized state structure was historically often considered *res nullius* by European powers, leading to colonization. However, modern international law and principles like self-determination challenge this view, recognizing rights of indigenous peoples.
Territory that is already under the sovereignty of another State, even if uninhabited or undeveloped, is *not* *res nullius* and cannot be acquired by occupation.
Discovery and effective occupation
Historically, mere discovery of new territory was sometimes considered sufficient to establish a preliminary title, giving the discovering State a limited time to follow up with effective control. However, under established international law, mere discovery is not sufficient for acquiring full sovereignty.
For occupation to confer a valid title, it must be accompanied by effective occupation. This requires the State claiming sovereignty to not only assert its claim but also demonstrate actual, continuous, and peaceful exercise of State functions over the territory. This involves:
- Taking possession (*animus occupandi*): The State must have the intention to act as sovereign and exercise control over the territory.
- Actual exercise of State authority (*corpus occupandi*): The State must perform acts of administration, such as establishing a government presence, enacting and enforcing laws, maintaining law and order, collecting taxes, building infrastructure, etc. These acts must be public and performed on a continuous basis over a period of time. The level of activity required for 'effectiveness' depends on the nature and accessibility of the territory (e.g., less may be required for remote or uninhabited areas compared to populated ones).
- Peaceful and Continuous: The exercise of authority must be peaceful (not challenged by other States) and continuous (not sporadic or temporary).
The classic case illustrating the requirement of effective occupation is the Island of Palmas Case (Netherlands v. United States) (1928), where the arbitrator held that while Spain may have discovered the island, the Netherlands had exercised continuous and peaceful display of state authority over the island since the 17th century, establishing a valid title through effective occupation, overriding the US claim based on succession from Spain's discovery.
Occupation as a mode of acquiring new, previously unclaimed territory is rare in the modern world, as most land areas are already under the sovereignty of a State.
Example 1. A State sends an expedition that is the first to reach and land on a remote, uninhabited island previously unknown to any State. The expedition plants the State's flag and claims the island. Is this State guaranteed to acquire full sovereignty over the island?
Answer:
No, this State is not guaranteed to acquire full sovereignty over the island based on discovery and planting a flag alone. While discovery might give a preliminary right, acquiring valid title through occupation requires effective occupation. The State must follow up its claim by establishing and continuously exercising State functions and authority over the island within a reasonable time. Mere symbolic acts like planting a flag are not sufficient to confer sovereignty; there must be actual administration and control over the territory.
Prescription
Prescription is a mode of acquiring sovereignty over territory that is actually under the sovereignty of another State, but which is adversely possessed by the acquiring State for a long period of time, effectively consolidating a title.
Long and continuous possession
Prescription is analogous to the concept of adverse possession in domestic property law. It requires the acquiring State to demonstrate several elements over a period of time:
- Possession must be exercised *à titre de souverain*: The possessing State must act as if it is the sovereign of the territory, exercising State authority openly and publicly.
- Possession must be actual: The possessing State must effectively exercise governmental functions over the territory, similar to the requirement for effective occupation.
- Possession must be continuous: The exercise of authority must be uninterrupted over a period.
- Possession must be peaceful: The exercise of authority must not be challenged or protested by the original sovereign. Acquiescence by the original sovereign is often seen as a key element.
- Possession must be public: The acts of sovereignty must be open and known.
- Duration: International law does not specify a fixed period for prescription. The required duration is assessed based on the circumstances, requiring sufficient time for the original sovereign's title to be extinguished through their failure to object to the adverse possession and the adverse possessor's exercise of authority.
Prescription is often a controversial mode of acquisition, particularly when the possession originates from an unlawful act (though some views argue that the passage of time and acquiescence can cure initial defects). It is seen as based on the principle of stability and the need for certainty in territorial boundaries, discouraging dormant claims by original sovereigns who fail to exercise their rights. The burden of proving acquisition by prescription is heavy on the State claiming title.
Example 1. State A has effectively and peacefully administered a certain border region for 50 years, exercising governmental functions like taxation and law enforcement, without any protest or challenge from State B, which claims historical title to the region. Can State A claim to have acquired title to the region by prescription?
Answer:
Yes, State A can claim to have acquired title to the region by prescription. The elements of long and continuous possession (*à titre de souverain*, actual, peaceful, public) are present. The lack of protest or challenge from State B for such a significant period (50 years) can be seen as acquiescence, extinguishing State B's original claim. While there is no fixed time period in international law for prescription, 50 years of unchallenged effective administration is a strong basis for claiming title through prescription, which aims to provide stability and certainty to established territorial realities.
Cession
Cession is the transfer of sovereignty over State territory from one State to another by agreement. It is a voluntary mode of acquisition, based on the consent of the transferring State.
Transfer by treaty
Cession is typically effected by a treaty between the ceding State (the State transferring the territory) and the acquiring State. The treaty must clearly express the intention to transfer and accept sovereignty over the specified territory. The transfer of sovereignty usually takes effect upon the entry into force of the treaty or on a date specified in the treaty.
Example: The transfer of territory from one State to another following a peace treaty after a conflict, where the defeated State agrees to cede territory as part of the settlement. The sale of territory (e.g., the purchase of Alaska by the United States from Russia in 1867) is also a form of cession.
The transferring State must have valid title to the territory it is ceding. A State cannot cede territory over which it does not possess sovereignty. The principle of self-determination of peoples also limits the ability of a State to cede territory inhabited by a distinct population if that population has a right to self-determination which would be prejudiced by the transfer.
Cession can be distinguished from other situations like lease of territory (where only control, not sovereignty, is transferred) or military occupation (where temporary control is exercised without transfer of sovereignty). The key is the voluntary transfer of sovereignty by treaty.
Example 1. Following negotiations, State C and State D sign a treaty under which State C agrees to transfer sovereignty over a border region to State D. Upon ratification of the treaty, State D takes administrative control of the region. How has State D acquired title to this region?
Answer:
State D has acquired title to the border region by Cession. Cession is the voluntary transfer of sovereignty over territory from one State to another, typically by treaty. State C voluntarily agreed to transfer its sovereignty over the region to State D through the treaty, and the transfer became effective upon ratification and State D taking control. This is a classic example of acquisition of territory by cession based on agreement.
Accretion
Accretion is a mode of acquiring sovereignty over territory through natural gradual processes, resulting in the addition of new land to existing territory.
Natural or artificial addition to territory
Accretion occurs when new land is formed or existing land is extended due to natural geographical processes like:
- Depositing of soil by rivers (alluvion): Gradual accumulation of sediment along riverbanks or deltas, adding to the landmass.
- Volcanic activity: Formation of new islands within a State's maritime zone or extension of existing coastal land due to volcanic eruptions.
- Movement of river beds: A gradual shift in a river course can alter the boundary between States if the boundary is defined by the river.
The key is that the process must be gradual and natural. Sudden changes (avulsion), like a river abruptly changing course, do not automatically change boundaries, which would remain on the original riverbed.
While historically focused on natural processes, some discussions exist about whether artificial additions to territory (e.g., land reclamation from the sea) can be considered a form of accretion conferring title, particularly within areas already under the State's sovereignty. However, the primary concept of accretion in international law refers to natural processes.
Acquisition by accretion is based on the principle that gradual, natural changes to a State's territory automatically become part of that State's sovereign territory, adjusting boundaries accordingly, especially if the boundary is defined by a river or coastline affected by the process.
Example 1. A river forms the border between State E and State F. Over several decades, natural silt deposits have gradually added a significant amount of land to State E's side of the river. Can State E claim sovereignty over this newly formed land?
Answer:
Yes, State E can claim sovereignty over this newly formed land by Accretion. Accretion is the acquisition of territory through natural, gradual processes like the deposit of soil by a river. Since the land was added gradually and naturally to State E's existing territory, and the river is a boundary, the boundary is considered to have moved with the riverbank, and the new land becomes part of State E's sovereign territory.
Conquest and Occupation
Historically, Conquest (taking territory by force) followed by military occupation and subsequent annexation was recognized as a mode of acquiring valid title to territory in international law. However, this mode of acquisition is now largely obsolete and illegal under modern international law, particularly after the adoption of the UN Charter.
Illegality in Modern International Law
The UN Charter (Article 2(4)) prohibits the threat or use of force against the territorial integrity or political independence of any State. This prohibition is a fundamental principle of modern international law and is considered a norm of *jus cogens*. Consequently, territory acquired solely through the unlawful use of force is not recognized as validly acquired territory in international law.
Mere military occupation of territory during an armed conflict does not transfer sovereignty. Military occupation is a temporary situation regulated by international humanitarian law (e.g., Fourth Geneva Convention, 1949), where the Occupying Power has duties towards the population and the territory, but does not acquire sovereignty. Annexation of occupied territory acquired by force is illegal and void under international law.
Example: State G invades and occupies a part of State H's territory by force. State G declares the annexed territory as part of its own State. Under modern international law, State G does not acquire a valid title to this territory through conquest and annexation based on the unlawful use of force. State H retains its sovereignty over the territory, and the international community generally does not recognize the annexation.
While historical instances of acquisition by conquest exist from periods when the use of force was not prohibited as stringently, it is no longer considered a lawful mode of acquiring territory today.
Example 1. Following a military conflict, State J occupies and annexes a significant portion of State K's territory, which State K claims it had historical title over. State J's use of force is widely condemned as a violation of the UN Charter. Can State J claim to have acquired valid title to the annexed territory?
Answer:
No, State J generally cannot claim to have acquired valid title to the annexed territory. Under modern international law, acquisition of territory solely by the unlawful use of force (conquest) followed by annexation is illegal. The UN Charter prohibits the use of force against the territorial integrity of a State. State J's annexation would be considered void under international law, and State K would retain its sovereignty over the territory. Other States would likely refuse to recognize the annexation, in line with the principle of not recognizing situations created by the unlawful use of force.
Adjudication
Adjudication, specifically by international courts or tribunals, can be a mode of settling disputes over territorial titles and, in doing so, confirm or clarify which State possesses sovereignty over a disputed territory.
Determination of Title by International Courts
When two or more States have conflicting claims to the same territory, they may agree to submit their dispute to an international court, such as the International Court of Justice (ICJ), or to an arbitral tribunal. The court or tribunal will examine the evidence and arguments presented by the States based on various principles of international law (e.g., treaties, historical practice, effective occupation, maps, geographical factors, principles of equity) and determine which State has the valid title.
The decision of the international court or tribunal is legally binding on the States that are parties to the dispute, provided they have consented to the court's jurisdiction. The judgment clarifies the legal status of the territory under international law and legally settles the dispute over sovereignty.
Example: The ICJ has decided several cases involving territorial disputes between States, determining sovereignty over islands, border regions, and maritime areas (e.g., the Frontier Dispute case between Burkina Faso and Mali, the dispute over Pedra Branca/Pulau Batu Puteh between Malaysia and Singapore). The judgment in such cases legally vests or confirms sovereignty in one of the claimant States.
Adjudication does not create new territory, nor does it transfer territory in the way cession does based on agreement. It authoritatively determines existing legal rights to territory based on established modes of acquisition or other relevant international legal principles.
While technically not a primary mode of *acquiring* new territory ex nihilo, it is a crucial legal mechanism for settling disputes over *existing* territory and confirming valid title, which is a form of legal acquisition or confirmation of sovereignty.
Example 1. State L and State M both claim sovereignty over a small island based on different historical events and subsequent activities. They agree to submit their dispute to the International Court of Justice. After hearing both sides, the ICJ issues a judgment declaring that State L has a stronger legal title to the island based on historical evidence and continuous administration. What is the effect of this judgment on the sovereignty of the island?
Answer:
The effect of the ICJ's judgment is to definitively settle the dispute over sovereignty and legally confirm that State L has sovereignty over the island. This is acquisition (or confirmation) of title by Adjudication. The ICJ's decision is legally binding on both State L and State M, and it provides a definitive determination under international law regarding the legal status of the island. State L's sovereignty over the island is now legally established relative to State M's claim, based on the Court's authoritative interpretation of the relevant facts and international law principles.
Loss of State Territory
Cession
Just as a State can acquire territory, it can also lose territory. The loss of territory by one State often corresponds to the acquisition of that territory by another State. Several modes through which a State can lose territory mirror the modes of acquisition, viewed from the perspective of the State losing the territory.
Cession is a mode of losing territory through the voluntary transfer of sovereignty to another State.
Voluntary transfer
Cession, from the perspective of the State losing territory, is the voluntary act of relinquishing sovereignty over a specific part of its territory to another State. This is typically done through a treaty, which expresses the consent of the ceding State to transfer sovereignty. The transfer must be voluntary, not under coercion (although cession after defeat in war as part of a peace treaty settlement has historically been considered valid, raising questions about the 'voluntariness' in some instances). Under modern international law, a treaty of cession concluded under the threat or use of force in violation of the UN Charter would likely be considered invalid.
Example: A State may cede a border region to a neighboring State as part of a boundary settlement agreement or in exchange for something else (e.g., money, other territory, resolution of a dispute). The State party to the treaty that transfers the territory loses its sovereignty over that territory upon the treaty taking effect.
The principle of self-determination of peoples is relevant here; a State's ability to cede territory may be limited if it affects the fundamental rights of a population residing in that territory.
Example 1. State A and State B, after prolonged border negotiations, sign a treaty in which State A agrees to transfer sovereignty over a small uninhabited island to State B in return for State B renouncing its claim over another disputed area. Upon the treaty coming into force, does State A lose sovereignty over the island?
Answer:
Yes, State A loses sovereignty over the island. State A has voluntarily agreed to transfer sovereignty over the island to State B through a treaty as part of a negotiated settlement. This is a voluntary transfer of territory by agreement. Upon the treaty entering into force, State A relinquishes its sovereignty, and State B acquires it. This is a loss of territory by Cession from State A's perspective.
Conquest and Occupation
From the perspective of the State losing territory, Conquest refers to the defeat of a State in armed conflict, leading to the acquisition of its territory by the victor State through force. Military Occupation refers to the exercise of control over territory during or after a conflict.
Loss of Territory by Force (Historically Valid, Now Illegal)
Historically, a State could lose territory if another State successfully conquered and annexed it. The conquered State would cease to exercise sovereignty over the lost territory, and the victor State would acquire title. However, as discussed under acquisition, conquest as a mode of acquiring territory is no longer lawful under modern international law (UN Charter prohibition on the use of force).
Consequently, a State does not legally lose sovereignty over its territory merely because another State has militarily occupied or purported to annex it through the unlawful use of force. The original State retains its sovereignty over the territory under international law, even if it is unable to exercise effective control due to foreign occupation.
Example: If State X invades and occupies a portion of State Y's territory, State Y does not legally lose sovereignty over that territory by conquest. State Y remains the sovereign, and the occupation is a violation of international law. The territory remains legally part of State Y.
Therefore, while a State may lose *effective control* over territory due to conquest and occupation, it does not legally lose *sovereignty* over it under modern international law based solely on the unlawful use of force by another State.
Example 1. A portion of State C's territory is militarily occupied by State D following an armed conflict initiated by State D in violation of international law. State D establishes its own administration in the occupied territory. Has State C lost sovereignty over this territory?
Answer:
No, State C has not legally lost sovereignty over this territory. Military occupation resulting from the unlawful use of force does not transfer sovereignty under modern international law. State C retains its sovereignty over the occupied territory. State D's occupation is temporary and governed by international humanitarian law. The territory remains legally part of State C, even though State C is unable to exercise effective control due to the occupation.
Subjugation
Subjugation is related to conquest. It refers to the acquisition of territory by a victor State after a war, where the defeated State is completely extinguished and its territory is absorbed into the victor State. Historically, subjugation, if complete and followed by effective control and possibly recognition by other states, could lead to loss of statehood for the defeated State and acquisition of its territory by the victor.
Total Absorption of Defeated State
Subjugation is a mode of losing territory that occurs when a State is entirely defeated in war and ceases to exist as a sovereign entity, its entire territory falling under the control of the victor State, which then incorporates it. This implies the complete extinction of the international personality of the defeated State.
Example: If State E completely defeats State F in war, dissolves its government, and occupies its entire territory, incorporating it into State E, State F would cease to exist as a State, losing all its territory by subjugation.
Like conquest, subjugation as a lawful mode of terminating a State's existence and acquiring its territory is also highly questionable under modern international law due to the prohibition on the use of force and the protection of State sovereignty and territorial integrity. The international community is unlikely to recognize the complete extinction of a State solely through unlawful military force.
However, if a State voluntarily merges with another State after a period of association or even post-conflict, this would be closer to voluntary union or absorption rather than unlawful subjugation through force.
In practice, the complete extinction of a State solely by conquest and subjugation is now considered illegal under international law. A State may lose territory to another State through voluntary cession as part of a peace treaty, but not through the mere fact of military defeat and forceful annexation of its entire territory if that force was unlawful.
Example 1. State G completely defeats State H in a war initiated by State G in violation of the UN Charter. State G occupies all of State H's territory, dissolves its government, and declares that State H no longer exists, and its territory is now part of State G. Has State H lost its statehood and territory by subjugation in a manner recognized as lawful by modern international law?
Answer:
No, under modern international law, State H has not lawfully lost its statehood or territory by subjugation based on State G's unlawful use of force. The prohibition on the use of force protects the territorial integrity and political independence of States. The international community would generally not recognize the extinction of State H or State G's title to its territory as a result of unlawful conquest and purported subjugation. State H would legally continue to exist, albeit under foreign occupation, and its territory would legally remain its own, even if it lacks an effective government operating freely within its territory. The principle of effectiveness in government might be temporarily suspended in such cases where the State's government is displaced by unlawful force.
Emancipation of Territory
Emancipation of Territory refers to the loss of sovereignty over a territory when that territory gains independence and becomes a new State. This is particularly relevant in the context of decolonization and the exercise of the right to self-determination by peoples.
Territory Gaining Independence
This mode of loss occurs when a territory that was under the sovereignty of a colonial power or a metropolitan State achieves independence, usually through an act of self-determination by the people of that territory. The original sovereign State loses sovereignty over that territory, which becomes the territory of the newly independent State.
Example: India gained independence from British rule in 1947. The United Kingdom lost sovereignty over the territory of India, which became the territory of the new independent State of India. Similarly, numerous colonies in Africa, Asia, and other parts of the world gained independence in the mid to late 20th century, resulting in the loss of territory for the former colonial powers and the emergence of new States.
Emancipation is closely linked to the principle of the right to self-determination of peoples, which is a fundamental principle of international law. A people in a non-self-governing territory or under foreign occupation has the right to freely determine their political status and pursue their economic, social, and cultural development, which may include the right to establish an independent State. When this right is exercised, the former administering power loses sovereignty over the territory.
This mode of losing territory is distinct from cession (voluntary transfer by agreement between existing States) or subjugation (historically, loss through complete defeat in war). Emancipation arises from the assertion of independence by a dependent territory and its people.
Example 1. A territory that has been administered as a non-self-governing territory by State J for several decades holds a UN-supervised referendum where the people of the territory overwhelmingly vote for independence. Following the referendum, the territory declares independence and is recognized by many States. Has State J lost sovereignty over this territory?
Answer:
Yes, State J has lost sovereignty over this territory. The people of the territory exercised their right to self-determination through the referendum, leading to the territory gaining independence and forming a new State. This is a loss of territory by Emancipation from State J's perspective. The former administering power loses sovereignty when the dependent territory achieves statehood through the exercise of self-determination, especially when supported by the international community and recognized by other States.
Abandonment
Abandonment, also known as Dereliction, is a mode of losing sovereignty over territory when a State intentionally gives up its claim and ceases to exercise effective control over it.
Intentional Giving Up of Sovereignty
For loss of territory by abandonment to occur, two elements are generally required:
- Intention to abandon (*animus derelinquendi*): The State must have a clear and unequivocal intention to relinquish its sovereignty over the territory. This intention is difficult to prove and is not presumed lightly. It requires evidence that the State no longer considers itself the sovereign.
- Actual relinquishment of authority (*corpus derelinquendi*): The State must cease to exercise effective governmental functions and control over the territory. This is the factual element, demonstrating that the State has withdrawn its administration and presence.
Both the intention and the actual cessation of control are necessary. Mere failure to exercise authority for a period, or temporary withdrawal, is not sufficient if the State retains the intention to maintain sovereignty and has not publicly or implicitly indicated abandonment.
Loss of territory by abandonment is relatively rare, as States are generally reluctant to give up territory. However, if a State genuinely decides it no longer wants or can exercise sovereignty over a remote or inaccessible territory, and ceases all administrative activities there, it could be considered abandonment. The territory would then become *res nullius* and potentially open for acquisition by occupation by another State.
Example: If a State withdraws all its personnel and administration from a remote island over which it previously claimed sovereignty, and publicly declares it no longer wishes to claim the island, it could lose sovereignty by abandonment. Another State could potentially acquire sovereignty over the island through effective occupation if it meets the requirements for occupying *res nullius* territory.
Abandonment is a unilateral act of the State losing the territory, signifying its deliberate relinquishment of sovereign rights.
Example 1. State K claims sovereignty over a small, uninhabited, and geographically challenging island. It has not sent any personnel, collected any data, or exercised any administration over the island for over a century. However, it continues to include the island in its official maps and occasionally issues diplomatic statements asserting its claim whenever another State shows interest in the island. Has State K lost sovereignty over the island by abandonment?
Answer:
No, State K has likely not lost sovereignty over the island by abandonment. While there is a long period of non-exercise of effective control (lack of *corpus derelinquendi*), State K's actions of including the island in its maps and issuing diplomatic statements asserting its claim indicate that it retains the intention to maintain sovereignty (*animus manendi*). For abandonment to occur, there must be a clear and unequivocal intention to relinquish sovereignty (*animus derelinquendi*). The mere lack of administrative activity, while potentially weakening a claim based on effective occupation or strengthening a claim by prescription by another state, does not, by itself, constitute abandonment if the State continues to demonstrate its intention to remain sovereign.