Standfirst:
Occupation law protects civilian populations and constrains an occupier’s powers. Settlement expansion, collective penalties, and starvation as a method of warfare are prohibited. Prolonged occupation heightens—not relaxes—these obligations and activates third-state duties.

Legal framework

  • Hague Regulations (1907), Arts 42–56: Powers and duties of the occupant.

  • Fourth Geneva Convention (1949): Protections for civilians; Art. 33 (collective penalties); Art. 49(6) (transfer of occupier’s civilians into occupied territory).

  • ICJ, Legal Consequences of the Construction of a Wall (Advisory Opinion, 2004): IHL and IHRL apply; third states must not recognize the unlawful situation and must not render aid or assistance in maintaining it.

  • UNSC Res. 2334 (2016): Settlements have no legal validity; calls for differentiation between the territory of the occupying state and occupied territory.

  • ICRC Customary IHL; San Remo Manual (1994): Blockades must not starve civilians or cause disproportionate harm relative to concrete military advantage.

Key legal consequences

  1. Settlements are unlawful under GC IV Art. 49(6). Derivative measures (land appropriation, demographic engineering) cannot be recognized by third states.

  2. Collective punishment is prohibited (GC IV Art. 33).

  3. Starvation as a method of warfare is prohibited (AP I Art. 54; Rome Statute Art. 8(2)(b)(xxv)).

  4. Blockades that foreseeably deprive civilians of essential supplies or cause excessive harm are unlawful.

Duties of third states

  • Non-recognition and non-assistance regarding unlawful situations arising from settlements/annexation.

  • Ensure respect for IHL (Common Art. 1), including through trade differentiation and due diligence to avoid benefiting from settlement economies.

  • Accountability support: Evidence preservation, cooperation with international mechanisms, and targeted, lawful restrictive measures where appropriate.

Policy tools

  • Procurement and trade exclusion lists for entities operating in unlawful settlements.

  • Humanitarian access packages and scalable corridors consistent with the San Remo Manual and IHL safeguards.

  • Public guidance to companies on heightened due-diligence duties in occupied territories.

Editor’s note (opinion): A coherent policy mix—non-recognition + non-assistance + lawful countermeasures—changes incentives on the ground and limits complicity risks for third states.

References 

Hague Regulations (1907); Fourth Geneva Convention (1949) Arts 33, 49(6); ICJ Advisory Opinion (2004); UNSC Res. 2334 (2016); ICRC Customary IHL; San Remo Manual (1994); Additional Protocol I Art. 54; Rome Statute Art. 8(2)(b)(xxv).