Provide a brief answer on the modes of territorial acquisition or change in traditional and modern international law.

Answer: There are five modes of territorial acquisition in traditional international law, including preemption, prescription, addition, cession, and conquest. Pre-occupation is when a state takes possession of terra nullius and acquires territorial sovereignty over it. The object of preemption is terra nullius and the criterion is effective possession. Limitation is the acquisition by a State of territorial sovereignty over a part of the territory of another State which the possessor has continued to occupy securely for a considerable period of time. Addition is the increase or enlargement of a State's territory by natural action or man-made measures. Cession is the transfer of a State's territory to another State by treaty. Conquest is the occupation by force of all or part of the territory of another State and the acquisition of sovereignty over that territory by annexation after war.

Modern international law has given rise to a number of new modes of territorial change, including proto-colonies, mandates, trust territories the realization of self-determination of peoples to become newly independent states, and referendums. The object of self-determination of peoples is the oppressed peoples under foreign subjugation and colonial rule; and referendum means that international law recognizes that the inhabitants of a territory vote to determine the ownership of that territory under certain conditions.