The legal requirements of self-defence

What Are The Legal Requirements Of Self-Defence?

Discuss, Making Reference To Relevant Case-Law.


Self-defence is one of the exceptions "legitimate" on the principle of prohibition of the use of force to resolve international disputes. This was confirmed by State practice, and the rules of international law and treaties establishing international organizations.

Before the emergence of the United Nations, the resort to military force in the international arena was an ordinary tools to implement the policies of nation-states and to end their differences; which made the power to had crucial roles at the level of management of international conflicts and disputes; despite some international efforts made in the framework of the Convention (Drago Porter) in 1907, which emphasized the prohibition of the use of force to recover debts, as well as the League of Nations which characterized between the legal and illegal wars, then the Charter (Kellogg-Briand) in1928, which tried unsuccessfully to restrict the use of force in international relations().

The outbreak of the Second World War revealed the limitations and the fragility of these efforts and attempts; this why the United Nations body makes the most urgent priorities to counter-violence and use of force in international relations. In this context, Article 2 of the Charter in paragraph 4 states that:

"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"().

This Article shows that the Charter not only prohibit the resorting to use force, but denied even the mere threat of using force, regardless the causes lead to this use of force. But the same Article include an indication to some exceptions to use force, this use which consistent "with the purposes of the United Nations".

That what lead to the exceptional and legitimate cases provided by the Charter: a situation of legitimate defense of individual or collective (Article 51 of the Charter) and the case of the United Nations intervention to address threats to peace
and security or prejudice to them, or acts of aggression in the framework of the so-called system of collective security (Articles 41 and 42 of the Charter).

Article 51 of the UN Charter read: "Nothing in the present Charter shall impair the inherent right of individual or collective self-defense 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…"().

Although the Charter grants the States (individually or in groups) the right of legitimate self-defence, it put some conditions to restrict and control the use of this right; to prevent the using of this right for aggression purposes, and to achieve strategic interests.

Because of this Article 51 continue to read: "…Measures taken by Members in the exercise of this right of self-defense 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"().

This paper tried to shed lights on the legal requirements of self-defence in International law, and according to the Charter of the United Nations, with discussion some practical cases of using the right of self-defence in international relations.

The Concept Of Self-Defence

The concept of Self-Defence does not aim to define the conditions in which the competent organs of the collective security will take action to maintain international peace and security, but rather to define the situations in which the state, acting without the authorization of those competent organs, may use force to protect those essential rights on which its security depends. The essence of this concept is that it is concerned with legal responsibility, the right of self-defence presupposes the delictual character of the conduct of states against which action is taken, and questions of convenience, desirability, or political wisdom are irrelevant to it. Moreover, the criterion of self-defence, namely the imminent or actual danger to the state's security, has no necessary coincidence with the criterion of collective, has no necessary coincidence with the criterion of collective action for the restoration or maintenance of international peace and security().

The discussion of self-defense should begin by distinguishing between an excuse and a justification for having committed an apparently criminal act. For the pragmatist there is not much difference between an excuse and a justification—proving either one leads to a criminal defendant's acquittal. Philosophically, however, the two are quite distinct. An excuse reduces a defendant's responsibility for his crime by showing that he was not acting fully of his own volition or that he did not know what he was doing. The law in such cases affirms that the act was wrong, but finds that the defendant's situation at the time of the act excuses him from responsibility. If an act can be justified rather than excused, however, then no crime occurred at all. Thus, the moral stakes for justification are higher because in finding justification the law affirms that a particular, apparently wrongful act was not merely excusable but in fact the right thing to do().

The origins of self-defence can be found in every legal system. in broad terms, it can be defined as a residual form of direct self-help permitted to a private individual whenever timely intervention by the centralized authority is impossible().

The right of self-defense in customary international law, was first clearly articulated in the 1837 Caroline incident involving the United States and England for an American ship sunk by the British(). The British claimed self-defense on the grounds that the Caroline was being used by rebels planning to attack Canada. U.S. Secretary of State Daniel Webster rejected this claim and argued that self-defense only comes into play where there is a “necessity of self-defense, instant, overwhelming, leaving no choice of means and no moment for deliberation.” He further stated that a claim of self-defense required that the defending state “did nothing unreasonable or excessive.” This formulation became the definition of the right of self-defense in customary international law().

According to Yoram Dinstein, the legal notion of self has its roots in interpersonal relations, and has been sanctified in domestic legal system since time immemorial. From the dawn of international law, writers sought to apply this concept to inter-State relations, particularly in connection with the just war doctrine. But when the freedom to wage war was countenanced without reservation in 19th and early 20th centuries, concern with the issue of self -defence was largely a metajuridical cal exercise().

In his study about "Self-Defence In International Law", D W Bowett indicated that self-defence existed only as a privilege justifying action other wise illegal, and the purpose of the privilege was the protection of certain rights stricto sensu. The condition precedent to the lawful exercise of the privilege was the breach of those established duties correlative to those rights, and there were legally recognized limitations on the privilege: for example, the limitation that the force used should be proportionate, and that it should not go beyond what was necessary to secure the protection of those rights().

According to Terry Nardin's philosophical approach to the question of aggression and self- defense, those subscribing to the narrower definition of self - defense are quality of defining peace as "merely absence of war" rather than the Kantian notion of "a state of peace" which is "social state in which aggression is not feared"().

On the other hand, many have argued that whatever the notion of self- defence had been in the 19th century, its meaning and scope had drastically changed in the years following the end of First World War, Judge Taoka points out that "the right of self-defence newly conceived after World War I emerged upon an entirely different ideological basis than that of the one which existed before the war().

In contemporary international law the concept enjoys primary importance and is set forth in Article 51 of the United Nations Charter. Agent from the fact self-defence constitutes the main exception to the general prohibition against the use of force, it is, according to most authorities, practically the only circumstances in which individual States can resort to armed force without previous authorization by the centralized authority().

Charter grants a right of “individual or collective self-defence if an armed attack occurs against a Member of the United Nations.” The framers of the Charter envisioned this right as the sole exception to the prevailing norm of the Charter's prohibition on the use of force().

Article 51 And Self-Defence

Article 51 of UN Charter is the channel through which every individual State must pass if its use of coercion id to be deemed legal by the international community. This Article plays this screening role for the following reasons: it is the main exception to Article 2(4), the centralized enforcement machinery foreseen in Chapter VII of the Charter was never set up, and the Security Council has very often failed to reach a decision().

Article 2(4), promulgates the general obligation to refrain from the use of inter-State force. Article 51 introduces an exception to this norm by allowing Member States to employ force in self-defence in the event of an armed attack. Article 51 has became the main pillar of the law of self-defence in all its forms, individual as well as collective().

The Charter's inclusion of an "armed attack" requirement has been interpreted- though not universally- as limiting this preexisting right of customary law. Scholars have suggested that the use of this terminology, rather than the previously used, and more ambiguous, term "aggression", was intended to remove the determination of lawful self-defense from the ambit of Security Council discretion. Others have argued that Article 51 was intended to enshrine precisely the pre-existing right().

A basic disagreement exists between those authorities who contend that Article 51 limits the recourse to armed force in self-defence to those in stances where an armed attack has actually occurred (or is imminent), or whether as some authors contend. Article 51 does not limit the right to employ armed force in self-defence to cases where an armed attack has occurred or its about to occur. The disagreement is fundamental- even if it is largely of a theoretical nature().

McDougal and associates argue that purpose of drafting of article 51 of the Charter was not to narrow the provisions of customary law with regard to self-defence. They continue to point out that those subscribing to a more restrictive view of self-defence as derived from Article 51 of the Charter "proceed from the hypothesis that self-defence is an exception whose recognition tends to nullify the generally rule of prohibition of coercion and which must therefore be confined the narrowest limits().

Myra Williamson indicated that there is possible interpretation of Article 51, that the combined effect of Article 2(3), 2(4) and 51 of the UN Charter extinguishes any other right to resort to force, otherwise than in accordance with the strict letter of the Charter (the so-called "restrictive interpretation"). Proponents of the restrictive interpretation include Brownlie, Henkin, and Kelsen who consider that Article 51 contains the only right of self-defence permitted under the Charter().

According to Antonio Tanca, Article 51 is "inherent" and on the relationship of the "right" with that provision. There is no consensus on whether Article 51 simply has the function of referring to that right, thus leaving it to be defined by custom and therefore unchanged by the Charter, or alternatively whether it limits the right in any way. This question is strictly connected with the issue of whether the use of force in self-defence falls within the ambit of the prohibition set forth by Article 2(4) ().

Preemptive Self-Defence

Preemptive Self-Defense presents serious problems in implementation. It eliminates the immediacy requirement of traditional self-defense under international customary law. Preemptive self-defense also runs the risk of losing the proportionality element of traditional self-defense. Since threats in preemptive self-defense scenarios are unclear and have not materialized, determining a proportional response is difficult. Indeed, a nation would be tempted to err on the side of overreacting to potential threat rather than under-reacting().

Since 1945, most governments have refrained from claiming preemptive self-defence. In the 1956 Sues Crisis, the British government argued the Article 51 of the Charter did not restrict the customary right of self-defence (). In the first, Israel invoked a right of self-defence against guerrilla incursions from the Sinai that packaged conceptually as the "armed attack" which Article of the Charter stipulated as the necessary condition for the exercise of legitimate self-defence. Britain and France, however, relied on a supposed authority to act unilaterally to protect the rights of states, established by treaty and practice, to navigate the Suez Canal, aright they claimed to be threatened by Egypt's government().

The United States, concerned about establishing a precedent that other countries might employ, implausibly justified its 1962 blockade of Cuba as "regional peace keeping", the US justified its blockade on the basis of chapter VIII of the UN Charter, Article 51.(). We should indicate here that the US blockade of Cuba in 1962 was labeled a quarantine By American officials, relaying on the fact that under international law a "blockade" was considered an act of war, while a " quarantine" arguably had no legal significance().

Israel, concerned not to be seen as an aggressor state, justified the strikes that initiated the 1967 Six Day War on the basis that Egypt's blocking of the Straits of Tiran constituted a prior act of aggression(). In this war, Israel was the first to open fire, Nevertheless, a careful analysis of the events surrounding the actual outbreak of the hostilities (assuming that the factual examination was conducted, in good faith, at the time of action) would lead to the conclusion that the Israeli campaign amounted to an interceptive self-defence, in response to an incipient armed attack by Egypt (joined by Jordan and Syria) ().

According to John B. Quigley, Even if Israel had expected Egypt to attack, it is not clear a preemptive strike is lawful. The UN Charter, Article 51, characterizes armed force as defensive only of if it is used in response to an "armed attack". Most states consider this language to mean that a preemptive strike is unlawful. India, for one, asserted in General Assembly discussion of the June 1967 hostilities that preemptive self-defence is not permitted under international law. Most authorities agree with that view, though some say force may be used in anticipation of an attack that has not yet occurred but is reasonable expected to occur imminently. Israel did not face such a situation().

On 7 June 1981, eight Israeli air force pilots conducted a bold and dangerous raid deep into hostile territory. Hugging the ground to avoid detection, they flew more than 600 miles before dropping their bombs on a nuclear reactor under construction at Osirak, on the outskirts of Baghdad. The reactor was badly damaged, Iraq's nuclear programme was severely impaired, and none of the attacking planes were lost. Israel claimed preemptive self-defence for the strike on the basis that a nuclear armed Iraq would constitute an unacceptable threat, especially given Saddam Hussein's overt hostility towards the Jewish State().

Israel specifically invoked in the Security Council the right of anticipatory self-defence on the basis of Article 51 of the Charter. An official statement of the Israeli Government explained that Israel had been "forced to defend itself against the construction of an atomic bomb in Iraq, which itself would not have hesitated to use it against Israel and its population centers(). Iraq countered that self-defence was permissible only against an armed attack. The arguments of Israel were also rejected by the other sparkers. A number of delegations discussed the legal concept of anticipatory self-defence as an inherent right only if an armed attack occurs and that the notion of preemptive strikes was unacceptable().

In 1988, the United states similarly eschewed a clime of preemptive self-defence when it argued that the shooting down of an Iranian civilian Airbus by the USS Vincennes, although mistaken, had been in response to an ongoing attack by Iranian military helicopters and patrol boats().

The Gulf War if 1991 signaled a change, as in this case the Security Council was able to authorize member states to take police action to force Iraq to withdraw from Kuwait. The threat of the veto has prevented further collective action of this kind. In this case there is no permanent force at the disposal of the Security Council that may be sent to restore peace and order().

Since the Iraqi invasion of Kuwait, Security Council took serial of resolutions, it established extensive sanctions against Iraq by means of resolution 661 (1990), while simultaneously affirming the right of self-defence under Article 51. In resolution 665 (1990), furthermore, members states aiding Kuwait were "called upon" to use naval force in necessary to enforce the sanctions. And in resolution 678 (1999) the Council authorized states to use all necessary means to liberate Kuwait if Iraq did not withdraw its troops before 15 January().

On 31 October 1998, Iraq announced that it would stop cooperating with UNSCUM altogether. This promoted the US and UK to bomb Iraq in December 1998 (operation Desert Fox), strikes that continued throughout 1999().

The Un Secretary General, Kofi Annan, rightly condemned the joint US-UK operation in 1998 and announced that it was a sad day for the UN as well as the World, Undoubtedly, the US and the UK flagrantly violated Article 2(4) which outlaws all use or threat of armed force because the action did not conform to exceptions to the ban on the use or threat of force contained in Article 51, which preserves the right of self-defence().

Self-Defence And Confrontation Of Terrorism

In the aftermath of 9/11, the Security Council has interpreted Article 51 to allow for a right of self-defense against non-state-sponsored terrorism(). Use of Article 51 to defend a State's decision to use armed force against terrorists and terrorist havens is not novel. The Israelis used it in defence of its raid on Entebbe, as did the United States in attempting to justify its bombing of Libya. Such claims did not win a favourable response from the international community. ‘While the right of self-defence is referred to as being “inherent,” the UN Charter itself does not elaborate on what is meant by the use of the word “inherent.” It is clear that the word was intentionally used because the initial draft of Article 51 did not contain “inherent” but was changed to make the right of self-defence explicitly inherent().

The question that arises especially after the post-September 11 endorsements is: to what extent may a State lawfully respond with armed force against the State that has sponsored the terrorists deemed responsible for the attack? Under international law, the response of a targeted State is predicated on principles of self-defence, and these are in turn based on what the international community regards as the ‘inherent' right to ensure national security and the attendant duty to protect one's citizens from terrorist attacks.69 The norms of self-defence revolves around survival, and a State's inherent right to protect and defend its sovereignty this in turn brings into play the UN Charter regime on the use of force vis-à-vis terrorism().

According to Francis Lyall, and Paul B. Larsen, preemptive self-defence confrontation of terrorism is even more controversial, it differs from anticipatory self-defence in that it is not triggered by a specific event, but from a general apprehension of being attacked. This can occur between states. However, it is more difficult to see its application in relation to the "War on Terror", where some of those said to be involved are not states().

Terrorists are hard to track down. Terrorists are not state actors nor are they usually controlled by state actors; thus they cannot usually be deterred by striking at a particular country. In fact, in the past, the Security Council has refused to qualify an act of terrorism as an armed attack that could trigger a valid act of self-defense under Article 51 of the UN charter. Even in condemning the acts of September 11th as "heinous acts of terrorism," the General Council failed "to characterize the acts as an 'armed attack' under Article 51"().

The logic behind the refusal to characterize terrorist attacks as 'armed attack' is that no state has "effective control" over terrorists, and that an armed attack cannot occur without "substantial involvement" on the part of a state actor. This reasoning has been most clearly articulated by the International Court of Justice (ICJ) in a somewhat different context-determining whether the acts of armed rebels rise to the level of armed attack().

Since 2002, the United States has sought to develop a right of preemptive self-defence that extends to more distant uncertain changes, most notably those arising out of the combined threat of weapons of mass destruction and global terrorism. Although the so-called "Bush Doctrine" remains highly controversial, it has been endorsed by several other countries, notably Israel and Russia().

The Bush Self-Defense Doctrine or The State Department's "National Security Strategy of the United States of America", published in September 2002, describes the Bush administration's position on self-defense as follows: "We will cooperate with other nations to deny, contain, and curtail our enemies' efforts to acquire dangerous technologies. And as matter of common sense and self-defense, America will act against such emerging threats before they are fully formed…"().

The United States' military action in Afghanistan could fit under international law self-defense doctrine, or at least it has been accepted as such by other nations. Therefore, the war on Iraq was the first real example of Bush's preemptive self-defense doctrine. According to the Bush Administration's pre-war rhetoric, the biggest threat Iraq posed to the U.S. was its alleged pursuit of weapons of mass destruction and its connection to terrorism. The combination of the two make for a potent threat().

Preemptive self-defense not only undermines the restraint on when states may use force, it also undermines the restraints on how states may use force. Today states measure proportionality against attacks that have occurred or are planned. What measure can be used to assess proportionality against a possible attack? The state acting preemptively is making a subjective determination about future events and will need to make a subjective determination about how much force is needed for preemption. In the case of Iraq, the US plan calls for massive force to take over the whole country and eliminate its government().

Presumably, most states claiming the right to use force preemptively will cite the Iraqi invasion to argue they have the right to do the same. Only by eliminating an unfriendly foreign regime entirely can a state defend itself from all possible future attacks. Even states responding to actual armed attack could use this precedent to justify disproportionate responses that seek to overthrow foreign regimes().


"If All Countries Used Their Armed Forces Solely For Self-Defense,

There Would Be No War"()

The right of legitimate self-defense -as stated by Article 51- has a great significance under the Charter of the United Nations, in view of the fact that its a case of a few cases, in which States have the right to use force as an exception to what the Charter had established under article 2, paragraph 4.

Despite the acknowledgment of the legality of the exercise of the right of self-defense by states, whether individually or collectively, this right - in the light of its exceptional nature- were subject to many restrictions and conditions, in order to organize and control to ensure compliance and consistency of such use and as a special character, and also to ensure that the States respect the principle of prohibit the use of force or threat of force in international law.

Undoubtedly, the most important of these conditions is to restrict the right of self-defence in a single and specific framework, is in the case of actual armed attack. Hence, the State's right to self-defense can not be legally except in case where the State facing armed aggression, and thus would be out of the circle of self-defense, all acts of retaliation and revenge, or preemptive military action could be used to confront the impending potential aggression or threat of use of force and other situations that do not amount to aggression.

In the light of that, if a State invade the territories of other States and faced an armed attack by the "attacked" State or by residents of the occupied territories, the aggressor State would lost its right of self-defence in the face of this attack, on the basis of the legal principle of non bis and the legitimacy of the claim to exercise the right of self-defence in the face of self-defence.


- Alexandrov, Stanimir A., (1996), Self-Defense Against The Use Of Force In International Law, The Hague: Kluwer Law International.

- Arend, Anthony C., Beck, Robert J.,(1993), International Law And The Use Of Force: Beyond The UN Charter Paradigm, London: Routledge.

- Biegel, Stuart., (2003), Beyond Our Control?: Confronting The Limits Of Our Legal System In The Age Of Cyberspace, Cambridge, Mass. ; London : MIT Press.

- Blokker, Niels, (2005), The Security Council And The Use Of Force : Theory And Reality - A Need For Change?, Leiden: Nijhoff.

- Booth, Ken; Dunne, Timothy., (2002), Worlds In Collision : Terror And The Future Of Global Order, New York : Palgrave Macmillan.

- Bowett, D W., (2009), Self-Defence In International Law, Clark, NJ : Lawbook Exchange.

- Byers, Michael., (2005), Not yet havoc: geopolitical change and the international rules on military force, in: Armstrong, J D., et al, (ed), Force And Legitimacy In World Politics, Cambridge, UK : Cambridge University Press.

- Byers, Michael., (2005), War Law : Understanding International Law And Armed Conflict, Vancouver: Douglas & McIntyre.

- Charter of the United Nations.

- Coplin, William D., (1996), The Functions Of International Law: An Introduction To The Role Of International Law In The Contemporary World, Rand McNally.

- Cronin-Furman, Kathleen Renée., (2006), The International Court Of Justice And The United Nations Security Council: Rethinking A Complicated Relationship, Columbia Law Review, Vol. 106 Issue 2, p449 .

- Dinstein, Yoram., (2002), War, Aggression, And Self-Defense, Cambridge: Cambridge Univ. Press, p160.

- Dinstein, Yoram., (2002), War, Aggression, And Self-Defense, Cambridge: Cambridge Univ. Press, p161.

- Dugard, John., et al., (2007), International Law: A South African Perspective, Lansdowne, South Africa: Juta.

- Hague Academy of International Law,. (2004), Hague Yearbook Of International Law, Martinus Nijhoff Publishers.

- Holzgrefe, J L., (2005), Humanitarian Intervention Ethical, Legal, And Political Dilemmas, Cambridge: Cambridge Univ. Press.

- Karoubi, Mohammad Taghi., (2004), Just Or Unjust War? : International Law And Unilateral Use Of Armed Force By States At The Turn Of The 20th Century, Burlington, VT : Ashgate.

- Loveman, Brian., (2004), Strategy For Empire : U.S. Regional Security Policy In The Post-Cold War Era, Lanham, Md.: Scholarly Resources.

- Lyall, Francis; Larsen, Paul B., (2009), Space Law: A Treatise, Farnham, Surrey, England ; Burlington, VT : Ashgate.

- Maogoto, Jackson Nyamuya., (2003), War on the Enemy: Self-Defence and State-Sponsored Terrorism, Melbourne Journal of International Law, 4(2).

- Nardin, Terry., (1984), The Moral Basis of the Law of War, Journal of international Affairs, Vol. 37.

- O'Connell, Mary Ellen., (2002), The Myth of Preemptive Self-Defense, The American Society of International Law.

- O'Brien , John, (2001), International law, London: Routledge Cavendish.

- Quigley, John B., (1990), Palestine And Israel: A Challenge To Justice, Durham : Duke University Press.

- Salas, Claudio D., (2004), The Legality Of Aggression: Self-Defense In The Domestic And International Context, Atenea, Vol. 24 Issue 1.

- Schweigman, David., (2001), The Authority Of The Security Council Under Chapter VII Of The UN Charter : Legal Limits And The Role Of The International Court Of Justice, The Hague ; Boston : Kluwer Law International.

- Tanca, Antonio., (1993), Foreign Armed Intervention In Internal Conflict, Martinus Nijhoff Publishers.

- Williamson, Myra., (2009), Terrorism, War And International Law : The Legality Of The Use Of Force Against Afghanistan In 2001, Farnham, England ; Burlington, VT : Ashgate.

- Zarif-Khonsari, Mohammad-Javad., (1988), Self-Defense In International Law And Policy, Ph.D., University of Denver.