The Geneva Conventions apply to military occupations of the territory of a state party, whether it is a total or partial occupation.
The question whether an occupation exists must be determined on the basis of the prevailing facts: it does not depend on the subjective views of the parties involved or the lawfulness of the use of force.
No need for armed resistance
The law of occupation applies even when the occupation does not meet any armed resistance. The latter requirement is expressly provided for in Common Article 2(2) of the 1949 Geneva Conventions and builds on precedents of the Second World War. Rather than armed resistance, the determinative element is whether the occupation is hostile in the sense that foreign forces are present without the consent of the territorial state. In other words, lack of armed resistance cannot be interpreted as consent. Similarly, classification of a situation as an occupation does not change when part of the local population welcomes the occupying forces.
Elements of occupation
The Geneva Conventions do not define occupation. Instead, the elements of an occupation can be found in Article 42 of the 1907 Hague Regulations which affirms that ‘a territory is considered occupied when it is actually placed under the authority of the hostile army,’ which is interpreted as meaning that hostile foreign forces exercise effective control over a territory.
Three cumulative elements are used to determine whether a state exercises effective control:
- unconsented presence of foreign forces
- due to their presence, the local sovereign is unable to exercise its own authority
- the foreign forces impose their own authority. See T. Ferraro, ‘Determining the Beginning and End of an Occupation Under International Humanitarian Law’, 94 International Review of the Red Cross 885 (2012), p 134ff; T. Ferraro and L. Cameron, 'Article 2: Application of the Convention', ICRC, Commentary on the First Geneva Convention, 2016, §§ 302-303.
The capacity of the occupying power to establish and project its authority determines the territorial scope of an occupation. In many cases it is difficult to determine precisely which part of a territory is occupied. See T. Ferraro and L. Cameron, 'Article 2: Application of the Convention', ICRC, Commentary on the First Geneva Convention, 2016, §§ 314-317.