Charter of Economic Rights and Duties of States
GA Res. 3281(xxix), UN GAOR, 29th Sess., Supp. No. 31 (1974) 50 The General Assembly,
Each State has the right:
- (a) To regulate and exercise authority over foreign investment within its national jurisdiction in accordance with its laws and regulations and in conformity with its national objectives and priorities. No State shall be compelled to grant preferential treatment to foreign investment;
- (b) To regulate and supervise the activities of transnational corporations within its national jurisdiction and take measures to ensure that such activities comply with its laws, rules and regulations and conform with its economic and social policies. Transnational corporations shall not intervene in the internal affairs of a host State. Every State should, with full regard for its sovereign rights, cooperate with other States in the exercise of the right set forth in this subparagraph;
- (c) To nationalize, expropriate or transfer ownership of foreign property, in which case appropriate compensation should be paid by the State adopting such measures, taking into account its relevant laws and regulations and all circumstances that the State considers pertinent. In any case where the question of compensation gives rise to a controversy, it shall be settled under the domestic law of the nationalizing State and by its tribunals, unless it is freely and mutually agreed by all States concerned that other peaceful means be sought on the basis of the sovereign equality of States and in accordance with the principle of free choice of means..
https://www.aaas.org/sites/default/..._Economic_Rights_and_Duties_of_States_Eng.pdf
The "State" is not a corporation that only exists on paper, it is the people that are governed in that territory. And no where does it say it has the right to hold onto land seized in a war. But it is codified in...
...you cannot acquire land by force.