The principle of non intervention is part of customary international law. It also based on the principle of territory sovereignty of States. If force is used in the intervention, it also violates Article 2 (4) of the Charter.
Professor briefly list the grounds of intervention. They are as follows:
1. Self-preservation : the supreme interest of the States overrides law. The right of self preservation is more sacred than the duty of respecting the independence off other States. A State has a right to interfere in the internal affairs of another States where the security and immediate interest of the former are compromised. The danger must be direct and immediate, not contingent and remote. Leading case: Caroline deals with the rule of self preservation. The test laid down in this case is “a necessity of self defence, instant, overwhelming and leaving no choice of means and no amount of moment for deliberation. UK failed to prove this test and expressed its regret to the US.
2. Enforcement of Treaty Rights:
A state is justified in interfering in the internal affairs of the State if the provisions or any treaty oblige the former state to preserve the independence or neutrality of the latter.
2. Intervention by intervention:
Invitation by the lawful government of the States to intervene in its internal affair.
Example: India’s intervention in Maldives in 1987.
3. Ground of humanity:
Intervention based on humane considerations seems to be legal. It cannot be brought within th eoridnary rules of international law which does not impose an obligation to prevent barbarities in he neighbouring States. Ex: India’s intervention in east Pakistan during Bangladesh liberation war.
4. Protection of persons and property:
Protection the persons, property and interest of its nationals may provide justification for intervention. The necessity for protection may arise due to gross injustice or due to injury caused by unfair discrimination.
5. Intervention in civil war:
After the establishment of the UN, there is no justification for intervention by individual States in the civil wars of other states. The Charter prohibits the use of use against the territorial integrity or political independence of any States.
6. Collective intervention:
Collective intervention is permitted by the Charter of the United Nation i.e. the enforcement action under Chapter VII. These are interventions for checking illegal intervention, intervention against an immoral act, intervention to remove international nuisance and intervention to defend national honour or to protect the interest of the nationals abroad.