Kofi Annan, Secretary-General of the United Nations at the time of the 2003 Iraq conflict, wrote:

"No principle of the Charter is more important than the principle of the non-use of force as embodied in Article 2, paragraph 4 .... Secretaries General confront many challenges in the course of their tenures but the challenge that tests them and defines them inevitably involves the use of force."1

Article 2(4) of the UN Charter2 , which is accepted universally, prohibits the use of force by countries. Article 2(4)3 of the UN Charter reads as under:

"Article 2(4)

All members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the purposes of the United Nations."

However, Article 2(4) has two exceptions which are covered under Article 42, 43 and 51 of the UN Charter. Article 42, 43 and 514 are reiterated below:

Article 42

Should the Security Council consider that measures provided for in Article 41 would be inadequate or have proved to be inadequate, it may take such action by air, sea, or land forces as may be necessary to maintain or restore international peace and security. Such action may include demonstrations, blockade, and other operations by air, sea, or land forces of Members of the United Nations.

Article 43

  1. All Members of the United Nations, in order to contribute to the maintenance of international peace and security, undertake to make available to the Security Council, on its call and in accordance with a special agreement or agreements, armed forces, assistance, and facilities, including rights of passage, necessary for the purpose of maintaining international peace and security.
  2. Such agreement or agreements shall govern the numbers and types of forces, their degree of readiness and general location, and the nature of the facilities and assistance to be provided.
  3. The agreement or agreements shall be negotiated as soon as possible on the initiative of the Security Council. They shall be concluded between the Security Council and Members or between the Security Council and groups of Members and shall be subject to ratification by the signatory states in accordance with their respective constitutional processes."

Article 51

Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security. Measures taken by Members in the exercise of this right of self-defence shall be immediately reported to the Security Council and shall not in any way affect the authority and responsibility of the Security Council under the present Charter to take at any time such action as it deems necessary in order to maintain or restore international peace and security."

Article 415 of the UN Charter talks about the measures not involving the use of armed forces which the Security Council may adopt to maintain diplomatic relationship between the states. Such measures may include complete or partial interruption of economic relations and of rail, sea, air, postal, telegraphic, radio, and other means of communication, and the severance of diplomatic relations.

By collectively reading Articles 42, 43 and 51 of the United Nations Charter, the two exceptions to Article 2(4) can be categorized as the framework of the organization's collective security system and the self-defence claim. It can be said that the states have widely used the exception of 'Self-Defence' to use force against different countries, and the said exception continues to be widely in use.

This article aims to discuss use of force against the nonstate actors (or terrorist) in the form of 'Self-Defence' and highlight instances wherein different states have used the said exception. It is also important to note herein that the use of force by different countries in the form of intervention by invitation, use of force against non-state actors, etc. can also be said to be covered in the concept of self-defence.


"If we don't end war, war will end us."- H.G Wells

There has been a lot of discussion on whether selfdefence is a customary norm or a treaty norm, however, it can be said now that the concept of self defence is accepted as both.6 It can further be said that whenever the states have used force against each other, the 'exception' of self-defence has been invoked.7

A bare perusal of Article 51 would show that the Article itself points out some conditions subject to which the force of Self-Defence can be invoked. The said conditions can be categorised as under:

  • Whichever state is invoking the exception of self-defence, shall first report the same to Security Council, and the said condition has been followed by states without any defaults since the case of Nicaragua8
  • The exception of self-defence can be invoked only until the Security Council has taken action to restore and maintain international peace, therefore, it can be said the use of force by way of self-defence is only a temporary measure.
  • Even though Article 51 does not explicitly state so, however, the ICJ in several cases9 has reiterated that use of force by way self-defence has to be necessary and proportionate.

Use of Force against non-state act

It is an undisputed fact that the non-state actors or terrorists have caused an immense amount of trouble and suffering to the whole world in the last few decades. As a result of this, the states have fallen in a predicament as to how to deal with the terrorists in a foreign territory.

There have been numerous discussions on the issue whether it is right to use force on territory of a foreign state to protect one's own country from the armed attacks by terrorists.

The courts have started accepting the use of force against non-state actors as self-defence, after the infamous attacks of 9/11 in the United States and since then no new exceptions to use of force have been introduced.10

However, the primary issue that emerges from use of force against the non-state actors in the form of selfdefence is - when is it legal or illegal to use the exception of self-defence for using force in a foreign state or territory.

The most relevant instance on the said issue is the well-known case of Pulwama attack, wherein India used force against a foreign state, intruding its territory, in an act of self-defence against non-state actors. The said attack was said to be "unlawful armed reprisal in the guise of self-defence"11 However, India justifies its act under the exception "self-defence" to protect its own country from the armed acts of non-state actors.

Therefore, since the 9/11 attacks and till date it can be said, that the exception of self-defence has not only evolved but has also emerged as a means for the states to protect themselves and its citizens from the nonstate actors.

It can be concluded that a state should use power only when it is the last option left, because the constant use of force tends to become a never-ending cycle, as is evident from the situation between Russia-Ukraine (since 2014) and between India-Pakistan (since 1947).



2. https://www.un.org/en/charter-united-nations/, came into force on 24.10.1945

3. https://www.un.org/en/sections/un-charter/un-charter-full-text/

4. https://www.un.org/en/sections/un-charter/un-charter-full-text/

5. https://www.un.org/en/sections/un-charter/un-charter-full-text/

6. This can be assumed Article 51 reads as "inherent right of individual or collective self defence", which preserves the customary right of States

7. C.Gray, International Law and the Use of Force 4th edn (New York, 2018),121

8. Case Concerning Military and Paramilitary Activities in and Around Nicaragua (Nicaragua vs. United States of America) Merits Judgement, I.C.J Reports 1986

9. Nicaragua Case(para 194), Oil Platforms case(para 43), Armed Activities on the Territory of the Congo(para 147)

10. C.J. Tams, 'The Use of Force against Terrorists', (2009) 20 EJIL,360

11. Christian Henderson, Tit-for-Tat-for-Tit: The Indian and Pakistani Airstrikes and the Jus ad Bellum

Originally published on May 2020. Vol. XIII, Issue V

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.