Zemach: Can Occupation Resulting from a War of Self-Defense Become Illegal?

Ariel Zemach (Ono Academic College - Law) has posted Can Occupation Resulting from a War of Self-Defense Become Illegal? (Minnesota Journal of International Law, forthcoming). Here's the abstract:

Illegal occupation gives rise to a duty of the occupant to withdraw from the occupied territory immediately and unconditionally. International law has long recognized the illegality of occupation that results from an unlawful use of force by the occupying state. An emerging approach among international lawyers holds that occupation resulting from a lawful use of force by a state, in self-defense, may also become illegal. Proponents of this approach link the illegality of the occupation to violations on the part of the occupant of the prohibition on the use of force or of the right of peoples to self-determination. These violations are the result of policies carried out by the occupant amounting to de facto annexation of the occupied territory, manifested in refusal to engage in good-faith negotiations to end the occupation or in actions on the ground aimed at perpetuating the occupation (e.g., enabling the settlement of the occupant’s citizens in the occupied territory). Arguments that such conduct renders the occupation illegal have largely focused on the occupation of Arab territories by Israel.

This article argues that the purview of the notion of illegal occupation in international law does not extend to occupation resulting from the lawful use of force by a state in self-defense ("lawfully created occupation"). The article reviews the various theories presented in support of such an extension, but shows that state practice does not support the existence of a rule of customary international law providing that a lawfully created occupation may subsequently become illegal.

The author subscribes to the view that a policy of de facto annexation pursued by an occupant violates the right to self-determination, and possibly the prohibition on the use of force. Such violation leads to legal consequences, but these do not include the illegality of occupation. This article examines the rules of international law that determine the legal consequences of state conduct that violates international law, and shows that these rules do not accommodate an extension of the notion of illegal occupation to lawfully created occupation.

The article proceeds to argue that the introduction of a rule of customary international law providing that a lawfully created occupation may subsequently become illegal is inadvisable because such a norm would be full of uncertainty.