The Caroline Case in 1837 established principles regarding the circumstances in which the use of force may be justified by the self defence principle. The case involved an American Ship, which had been moored at American port when the British destroyed it. The Caroline had been involved in activities that included assisting rebels harass the Canadian authorities. Dixon and McCorquodale mention that ‘Webster’s formulation’ during correspondence is regarded as the ‘locus classicus’ of customary self-defence. The formulation consisted of two tests that needed to be satisfied in order to deem use of force, as self-defence.
Firstly, the test was one of necessity ‘[i]t will be for that Government to show a necessity of self-defence, instant, overwhelming, leaving no choice of means, and no moment for deliberation’. Secondly, it was necessary that the use of force in self-defence to be proportionate, as quoted from Webster’s letter ‘[i]t will be for it to show, also, that the local authority of Canada, even supposing the necessity of the moment authorized them to enter the territories of the United States at all, did nothing unreasonable or excessive; since the act, justified by the necessity of self- defence, must be limited by that necessity, and kept clearly within it’. This case distinguishes between the use of force as a means of self defence from those with the nature of reprisals. The general factors of this case are reflected in the UNCH, especially in Article 51, which refers to ‘inherent’ right of self-defence, and has been held by the ICJ to encompass customary international law.
In modern disputes the landmark case Nicaragua v USA was where the ICJ held that ‘the charter testifies to the existence of the right of collective self-defence in customary international law…’, and provided the injured state had requested assistance, there was no need for States to be directly affected to participate in collective self-defence. However, this matter was not clearly settled as Sir Robert Jennings in his dissenting judgment distinguished self defence from ‘vicarious defence’, and notes that ‘there should, even in “collective self defence”, be some real element of self…’. Gray a leading academic whilst believing the notion to be ‘far fetched’ in reality, states that many commentators agree with the approach taken by Jennings. Many states when using force in the territory of another, may claim the right of collective self-defence, however this justification can be used to abuse the power available to help protect and restore peace in weaker states.
The Nicaragua v USA case, as Cassese mentions elaborates the test on proportionality further. Firstly, victim states must not occupy the territory of the aggressor, unless this is strictly required to hold the aggressor in check, and to prevent the repetition and continuance of unauthorised use of force. Secondly, acts of self defence must be discontinued as soon as the SC step in with measures to restore the peace and security. It is worth noting that this does not include when the SC has merely passed opinion on the matter, rather when effective action is set. (As long as the SC has not taken these ‘effective’ measures, the victim state will be justified to continue acts of force in self-defence). Furthermore, the third factor requires that acts of self-defence must end as soon as it has fulfilled its purpose, and according to Article 51 UNCH, and corresponding customary law this must be as soon as the ‘armed attack’ has been resisted.
However, this case did not explore the degree of force required to classify an ‘armed attack’. This can be seen in Sir Jennings dissenting judgement, where he states ‘[t]he question of what constitutes ‘armed attack’ for the purposes of Article 51, and its relation to the definition of aggression, are large and controversial questions in which it would be inappropriate to become involved in this opinion’. However, he does distinguish between assisting rebels on another’s’ territory as possibly an ‘armed attack’, from situations where support is given without occupying territory which represents a threat and breach to peace. MacLean another leading academic has stated that this uncertainty may require the courts to follow the approach in this case with caution and perhaps limit it to the facts of the case in question. Although the problem here is that, the UNCH has not defined an ‘armed attack’ or the circumstances under which collective self defence maybe justified, whereas customary law had established principles prior to the advent of the UNCH. If the rules on the legal use of force have no clarity then this will leave them open to abuse, allowing perpetrators to justify extreme uses of force as self-defence.
In 1994, the UN General Assembly requested the Advisory Opinion of the ICJ on the question of whether ‘…the threat or use of nuclear weapons in any circumstances [are] permitted under international law?’. Cassese notes that out of the five possible justified reasons to use nuclear weapons, three are convincing. He mentions that states would be permitted to use nuclear weapons, when they believe they are about to be attacked by such weapons themselves, this can be classified as a pre-emptive attack. The second justifiable reason according to Cassese is when nuclear weapons or other weapons of mass destruction have been engaged to attack a state, and the third reason is to retaliate against an enemy’s use of weapons that constitute those capable of mass destruction, in the course of conventional war.
However, he also relates these back to legal principles and states that any use of weapons contrary to the rules in Article 2 (4) and customary law are illegal, as recognised by the ICJ in the Opinion. However, he recognises that the ICJ failed to comment on the use of nuclear weapons in an pre-emptive attack, as this is clearly contrary to the legal principle on the use of force. On the third issue he discusses how the SC have five permanent members whom all support the use of nuclear weapons in cases to prevent a ‘serious and imminent’ nuclear attack, and this example demonstrates the dangerous battle between policy and ‘better’ interpretation of the law.
The rules in Article 2(4) specifies a general prohibition on force, Article 51 on the other hand contains that it is the ‘inherent’ right of a state to protect itself (individually or collectively) in the event of an ‘armed attack’. However, it does not specify any prohibition of weapons and applies merely to the use of force; there are many weapons in the modern world that can threaten the very survival of a state (i.e. weapons of mass destruction).
The ICJ stated that the use of illegal weapons (those which were expressly prohibited by custom or convention) cannot be justified by ‘any situation’. It also discussed the proportionality principle and suggested that nuclear weapons were not necessarily prohibited in justified use of force (in reference to Article 51), as there may be a situation where the very survival of a state depended upon its engagement. However, it quashed notions asserted by some states that the use of nuclear weapons in the conduct of reprisals was legal. It did not feel the need to comment on this matter because reprisals just as self defence were governed by the principle of proportionality. This means that discretion is upon states to use nuclear weapons however, it is for the aggressor to take responsibility for the unnecessary use of force. It is noted that any use of force must comply with obligations under treaties including those on the use of nuclear weapons and humanitarian law.
The fact that the ICJ could not comment on whether the use of nuclear weapons would be legal in the most extreme circumstances caused Vice President Schwebel in his dissenting opinion to comment ‘[that] the court would have done better to have drawn on its undoubted discretion not to render an Opinion at all’. The question here is whether states can assert their power to use nuclear weapons in certain circumstances, and suggests that Cassese’s statement on the prohibition is not as strict as it suggests, if it were then there would be certainty in relation to its applicability but there is none on this matter to date.
According to a strict reading of Article 51 all measures relating to eliminating all possible threats are held exclusively by the SC, and pre-emptive force is not justified either collectively or individually. Measures in self-defence are only legitimate in response to an ‘armed attack’, which has already occurred. However, many commentators assert that in certain circumstances it would illogical or unreasonable to wait until an ‘armed attack’ has occurred. The Caroline Case sets out principles where the act of force in anticipatory self-defence would be permissible, if the imminence of danger were so grave. The test of necessity had opened floodgates to using force prior to an ‘armed attack’. The danger of this matter can be compared to pouring fuel on a fire; if pre-emptive attacks were used then it may begin a vicious circle of retaliation where force is justified as self-defence.
For example: President Kennedy in 1962 having acquired photographic evidence of the Soviet Unions plan to install missiles capable of hitting the US in Cuba, imposed naval ‘quarantine’ to prevent the delivery of weapons. They argued international provisions were not applicable, and it was a matter of domestic law. Another occurrence was in 1967, when Israel launched an attack on Egypt and other Arab countries after President Nasser moved troops closer to Israel. This has often been referred to as the ‘Six day war’ as Israel occupied the Sinai Peninsula, the West Bank, and the Gaza Strip during this period; it justified its actions as necessary to forestall an Arab invasion. In 1981, Israel bombed and destroyed a nuclear reactor under construction in Iraq. They asserted that Iraq had claimed to be in a state of war with Israel, and claimed Iraq denied the right of Israel to exist. Although Israel had argued to be protecting its ‘inherent’ right to survival, both the SC and General Assembly condemned the actions as ‘aggressive’.
Professor Akehurst argues a state can protect its nationals in other states as self-defence under Article 51. He argues that even under the restricted scope of Article 51 it may be possible to defend nationals abroad in self-defence, however it is necessary for action to be taken after an ‘armed attack’. An ‘armed attack’ on national abroad may constitute an attack on the state, as the ‘population’ in essence form part of the Statehood. However, on this argument Professor Akehurst does acknowledge that supporters of the restrictive school of thought do not believe the use of force to protect nationals abroad is legal.
An example can be seen in the Entebe Incident, where Israeli commandos rescued their nationals from a flight hijacked by Arab terrorists, which landed in Uganda. It was apparent that the authorities had made little attempt to help the victims, and indeed may have helped the terrorists. Although the SC had not passed comment on this matter, Israel sort to claim their ‘inherent’ right to self defence and defend their nationals abroad. Brownlie who is a leading commentator, mentions that ‘ it is very doubtful if the present form of intervention has any basis in modern law…it provides infinite opportunities for abuse.’ It is clear that conflicts between political issues, and legal principles are major obstacles that members of the world community must resolve, as this creates great uncertainty.
Another problem that has arisen is whether states can be held responsible for the actions of their members, it is thought that this is an issue of state responsibility. However, if the state in question lacks the provision to combat such threats, can the use of force by a third party be justified. An article written by Murphy after the atrocities of September 11th comments on how the US had regarded the attack as comparable to ‘military action’. SC Resolution 1368 on the 12th September condemned the ‘horrifying terrorist attacks’, and stated they were a ‘threat to international peace and security’. SC Resolution 1373 on the 28th September adopted measures under Chapter VII UNCH that obligated its members to deny finance, support, a ‘safe haven’ for terrorists and to share intelligence gained with other members.
It also established a SC committee to monitor the implementation of these measures. At no time did the SC authorise the use of force by the US or UK, although it did mention ‘combat by all means’. The problems that arise from terrorist activities is whether their ‘host’ state is responsible for their acts of force. On October 7th, the US declared itself a ‘victim of massive and brutal attacks’ and that it was exercising its right of self defence by taking actions against the Al’ Qaeda in Afghanistan. It argued that it had requested the Taliban not to allow Al’ Qaeda members to train (purely to harass peace abiding citizens) on its territory. The actions of the US and UK in response to the terrorist attacks, may be justified by self defence in Article 51 UNCH, but if the ICJ or SC fail to comment then the floodgate remains open.
Another area of great controversy is whether states may intervene in internal affairs on humanitarian grounds. For example India’s invasion of Pakistan in 1971 in support of the Bangladeshis, the Tanzanian intervention in Uganda, which led to the fall of the Idi Amin regime were based on humanitarian grounds, although these were clearly by-products of their intention. Although, the motives of states may be questioned in these circumstances, it is possible that two interests including self-defence can be served at once. Recent intervention in Kosovo, highlighted that Western states were only interested in providing humanitarian intervention in order to prevent the stability of eastern Europe being affected. The Gulf war can also be cited to be indicative of humanitarian concerns being by-products of interests.
As noted by Brownlie most academics are under the impression that it is not permissible to use force on humanitarian grounds. The Declaration on the Inadmissibility of Intervention in the Domestic Affairs of States, and the UNCH supports non-intervention, as the legal position. According to Article 51 UNCH proportionate force may be used to resist an ‘armed attack’, until further action is arranged by the SC. However, neither custom nor convention authorise states to use acts of force when there is a ‘threat or breach of peace’, this is one of the primary purposes of the UN. However, the rules are clearly not firmly established as the ICJ stated that ‘ Humanitarian aid…cannot be regarded as unlawful intervention’ in the Nicaragua Case, which is likely to prevail in future cases.
In conclusion, it is submitted that the ban laid down in Article 2(4), and customary law, which prohibits the use of force, is not as conclusive as Cassese’s statement suggests. Dr Franck states ‘[t]he rules, [although] admirable in themselves, were seemly predicted on a false assumption: that the wartime partnership of the Big Five would continue, providing the means for policing the peace…’, and asserts that Article 2 (4) ‘mocks us from its grave’. Since the creation of the UNCH, much has changed and developed, but in relation to Franck’s suggestion it may be held true to certain extent, especially during the Cold War when the SC had no power to enforce law (ie: Article 2 (4)) against perpetrators. He states the death was due to the power of Article 2(4) being eroded as a direct result of the rise in liberation wars, threat of total destruction wars, and the domination of super powers in regional systems. The certainty of Article 2(4) and corresponding customary law is extremely vital for the rule of law to prevail, as each state in practice have different opinions, and methods of interpretation.
Dixon and McCorquodale (2003) pg 37
Quoted in a CRS Report for Congress. D, Ackerman, International Law and the Pre-emptive Use of force Against Iraq. CRS Report for Congress, (2003) at pg 2
Dixon and McCorquodale (2003) Pg 521
H Duffy, Responding to September 11th: The Framework of International Law (2001) pg 4
UN Charter Preamble, Article 2 (3)
UNCH Article 92 – The ICJ is the ‘principle judicial organ of the United Nations’ and it is empowered to determine infringements…
B, Simma, NATO, the UN and the Use of Force: Legal Aspects EJIL (1999) pg 4
UNCH Article 39 – using force in accordance with Article 42 and non-forceful measures under Article 41.
Nicaragua v USA ICJ Rep 1986 14 para 200
Dixon and McCorquodale (2003) pg 520
Quoted in Dixon and McCorquodale (2003) pg529 : The Caroline Case 29 Brit & For St Papers
Dixon and McCorquodale (2003) pg 529
Quoted in Dixon and McCorquodale (2003) pg 530
Quoted in Dixon and McCorquodale (2003) pg 530
For example: the test of necessity and proportionality are not referred to in the charter and are rules of customary international law, however due to the use of the word ‘inherent’ in Article 51 the ICJ in the case of Nicaragua decided that they were still relevant. Refer to Nicaragua v USA ICJ Rep 1986 14 para 194
Nicaragua v USA ICJ Rep 1986 14 involved acts of force by the USA being brought before the ICJ, the actions included the mining of their waters, arming rebels, and so on, they justified that the acts were committed as ‘collective self-defence’ for El Salvador and Costa Rica. The ICJ subsequently rejected this argument, as it was necessary that victim states request assistance, additional to satisfying the test on necessity and proportionality (customary international), along with that of an ‘armed attack’ in Article 51.
Nicaragua v USA ICJ Rep 1986 14 para 104 -105, also refer to A, Cassese, ‘Legal Response to Terrorism’ 38 ICLQ (1999) 558 - Cassese also agrees that states wishing to intervene must obtain authorisation in the form of a request in order to use force legitimately in ‘collective self-defence’.
Nicaragua v USA ICJ Rep 1986 14 para 545
Dixon and McCorquodale (2003) pg 532
Quoted in Dixon and McCorquodale pg 534: Legality of the Threat or Use of Nuclear Weapons Opinion ICJ Rep 1996,
Cassese (2001) pg 335-336
Dixon and McCorquodale (2003) pg 534-537
Dixon and McCorquodale (2003) pg 536
O, Schachter, ‘The Right of States’, M.L.R (1984) pg 1634 Professor Schachter justifies anticipatory self defence by stating that there are situations where the imminence of an ‘armed attack’ is ‘so clear and the danger so great’ that ‘defensive’ action be necessary.
J, Paust, ‘Legal Responses to International Terrorism’ HJIL (1999) 22:1 pg 17 – discusses condemning action in terrorism.
M, Akehurst, ‘The Use of Force to Protect Nationals Abroad’ 5 IR 3 (1976/77)
Dixon and McCorquodale (2003) pg 539
Dixon and McCorquodale (2003) pg 542
Dixon and McCorquodale (2003) pg 539-542
Dixon and McCorquodale (2003) pg 546-549
Nanda, ‘Revisiting the validity of human intervention under international law’ (1992) DJILP 305 pg 306
Nanda, ‘Revisiting the validity of human intervention under international law’ (1992) DJILP 305 pg 334
T, Franck, “Who Killed Article 2(4)?” 64 AJIL (1970) pg809