The Use Of Force - International Law

Under the UN Charter (‘UNC’) Art 2(4), the threat or use of force by UN Member states against other states is prohibited. The law under Art 2(4) is also customary law and a norm of jus cogens (Nicaragua case)

States will still use force when the judge it is in their best interests to do so. However, overwhelmingly, they abide by the international rules regulating the use of force, or at least justify their acts by reference to the rule of law, as it is in their interests to do so.

To decide if [X] has prima facie breached Art 2(4), whether there has been a threat or use of force must be decided.

• If the envisaged use of force is itself unlawful, the stated readiness to use it would be a threat prohibited under art 2(4) (Nuclear Weapons Case)

• A threat is a breach if it is directed against the territorial integrity or political independence of a state, or is against the purposes of the UN (Nuclear Weapons Case)

  • This implies that a threat that, for example, is intended to protect against a humanitarian or environmental disaster, might not breach Art 2(4).

• Military manoeuvres near the border of a state, depending on the circumstances, may not amount to a threat of force (Nicaragua case)

• Participating in acts of civil strife involving threat of force amount to a ‘threat of force’ (Nicaragua case)

• Whether the possession of nuclear weapons for deterrence is a "threat" contrary to Article 2.4, depends on whether the use of force envisaged would be directed against the territorial integrity or political independence of a State, or against the Purposes of the United Nations or whether, in the event that it were intended as a means of defence, it would necessarily violate the principles of necessity and proportionality (Nuclear Weapons Case)

Use of force includes (per the Nicaragua case):

• the laying of mines in territorial waters

• attacking ports, oil installations or naval bases

• assisting insurrectionists by organising or encouraging the organisation of forces (including irregular forces or armed bands) for incursion into the territory of another state

• participating in acts of civil strife involving use of force

Use of force does not include (per the Nicaragua case):

• economic coercion

• the mere supply of funds to rebels (though it may be an act of intervention in the other state’s internal affairs).

The Security Council (SC) has the primary responsibility to take action to maintain international peace and security (UNC Art 24). Its powers in this area arise largely under Chapter VII of the UNC.

Has the SC determined the existence of a threat, breach or act of aggression?

Under UNC Art 39, the SC has the power to determine whether a threat to the peace, breach of the peace, or act of aggression exists and, if it does, must make recommendations, or decide what measures shall be taken.

• The SC can call upon the parties concerned to comply with provisional measures before making recommendations or deciding on measures: UNC Art 40

[Note if threat has been or may be determined]

Has the SC considered measures falling short of the use of armed force?

Once a threat is determined to exist, the SC may decide on what measures falling short of armed force may be taken in response and may call upon UN Member states to apply them (UNC Art 41). [Note if political difficulties eg one of the P5 – Russia, France, China, UK, USA – are likely to block the vote]

• Per the article, these measures may include:

  • complete or partial interruption of:

    • economic relations

    • rail, sea, air, postal, telegraphic, radio, and other means of communication

  • the severance of diplomatic relations

• The SC has also used Art 51 to set up the International Criminal Tribunals for the Former Yugoslavia and Rwanda

[Note if this has been done and failed]

Has force been/may it be authorised by the SC (and to what extent)?

If measures taken under Art 41 are inadequate (or it is apparent they will be), the SC can decide to take action by air, sea or land forces as necessary to maintain or restore international peace and security (UNC Art 42). [Note if political difficulties eg one of the P5 – Russia, France, China, UK, USA – are likely to block the vote]

• Per Art 42 this may include demonstrations, blockade, other operations

• Under UNC Art 43 all UN Members are required to make forces, assistance and facilities (including rights of passage) available as necessary; however there is no standing force since not state has negotiated an agreement with the SC as required by Art 43.

  • Members are required to have immediately available air force contingents under UNC Art 45, but this is not the case.

Implied authorisation?

States (including the US, UK and Australia) have occasionally argued that they may rely on the implied authorisation of the SC to use force where the SC has determined there is a breach of or threat to the peace under UNC Art 39, in that there is an implied authority to act if the SC fails to do so. There is, however, no authority for the use of force on this basis and most states reject this concept.

• Arguments seeking to revive very old SC Resolutions (it is...