BORDER IN INTERNATIONAL LAW

In international law, borders are legally defined lines or surfaces (land, maritime, or airspace) that separate the territorial sovereignty and jurisdiction of states. Established primarily through bilateral or multilateral treaties, these boundaries are protected by the principle of territorial integrity, which prohibits the threat or use of force to alter them, as enshrined in the UN Charter. 

Key Aspects of Borders in International Law

• Delimitation and Demarcation: Borders are established through a two-step process: delimitation (defining the boundary in a treaty) and demarcation (physically marking it on the ground).
• Territorial Sovereignty: A border defines the precise limit of a state's sovereign powers, where its laws apply exclusively.
• Types of Borders:
• Land Boundaries: Often defined by physical features or geodetic lines.
• Maritime Boundaries: Involve territorial seas, exclusive economic zones, and continental shelves, regulated heavily by the UN Convention on the Law of the Sea (UNCLOS).
• Airspace: Generally extends upwards to the limit of atmospheric space, typically 100-150 km.
• Legal Principles:
• Territorial Integrity: The inviolability of borders is a core principle, forbidding the annexation of territory by force.
• Uti Possidetis Juris: A principle often used in post-colonial contexts, holding that new states inherit the administrative boundaries they had prior to independence.
• Border Control and Function: While borders define sovereignty, they also serve as areas for exercising state functions, such as customs, immigration, and security controls.
• Disputes: When the exact location of a boundary is in question, it is a "boundary dispute." If the ownership of the territory itself is contested, it is a "territorial dispute". 

International law works to maintain stability by prioritizing the respect of established borders, even when they do not align with ethnic or natural divisions, with the aim of preventing conflict.