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Proportionality and the Use of Force in the Middle East Conflict
Proportionality and the Use of Force in the Middle East Conflict

JURIST Contributing Editor Mary Ellen O'Connell of Notre Dame Law School says that the principle of proportionality in the use of force is a necessary, sensible and humane doctrine of international law that Israel and Hezbollah would do well to respect in the latest Middle East conflict…

A number of world leaders responding to Israel’s forceful reaction to the Hamas and Hezbollah raids in recent weeks have called it justifiable but disproportionate. Applying the international law on the use of force supports both assessments. International law regulates both when force may be initiated (jus ad bellum) and how it must be conducted (jus in bello). The most important rule in either category may well be the principle of proportionality. Any use of force, to be lawful, must be proportionate.(1)

At the end of June, Hamas militants conducted a raid on Israel from Gaza, kidnapping an Israeli soldier. About two weeks later, Hezbollah militants based in southern Lebanon launched rockets into northern Israel and also conducted a raid, capturing two Israeli soldiers, killing three and wounding two. Israel responded to the first incident with heavy bombardment of Gaza, destroying the power station in addition to other civilian infrastructure and killing civilians. In response to the Hezbollah raid, Israel bombed Lebanon, including the city of Beirut in central Lebanon, Beirut’s port and airport. It imposed a maritime blockade. A week after the bombing of Lebanon began, Israeli tanks crossed into the southern Lebanon. Hundreds of Lebanese civilians had died by July 19, with no end to the Israeli action in sight. Hezbollah has launched counter-attacks, killing scores of Israeli civilians.


 Topic: Middle East Conflict | Video: Middle East crisis meeting [UN Security Council]

Israel had the right under international law to take defensive measures in response to the Hamas and Hezbollah raids. Any use of military force, however, must respect the principle of proportionality. This is a general principle of international law, meaning it is inherent to the system. It is also reflected in both treaties and customary international law. There is no question that it is binding on all parties using force. The principle prohibits attacking a military objective if doing so will result in a loss of civilian life, damage to civilian property or damage to the natural environment that outweighs the value of the objective. Our contemporary understanding of proportionality is informed by Article 51(5)(b) of the 1977 Additional Protocol I to the 1949 Geneva Conventions defining an indiscriminate attack. Such an attack is one “which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated.”

The principle of proportionality works in conjunction with other fundamental principles of international humanitarian law, including the principles of discrimination, necessity, and humanity. The principle of discrimination prohibits the intentional targeting of civilians, persons no longer taking part in fighting because of injury, surrender and the like, and civilian property. Additional Protocol I, Article 51(2) provides, “The civilian population as such, as well as individual civilians, shall not be the object of attack. Acts or threats of violence the primary purpose of which is to spread terror among the civilian population are prohibited.” Parties using armed force may only intentionally target military objectives, and, even then, the proportionality calculation must be applied: Will the “collateral” damage be too great to justify the attack?

Additional Protocol I Article 52(2) identifies military objectives, incorporating the principle of necessity: “Attacks shall be strictly limited to those objects which by their nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage.”

Basic humanity must also always be observed. The excessive use of force, targeting civilians, destroying civilian infrastructure and so forth are not only considered disproportionate, unnecessary, and indiscriminate, but also inhumane.

Closely related to these principles is the principle of proportionality as it relates to the decision to resort to force in the first place. It is important to note that the legal context in which the two raids took place differs. Israel had a stronger basis for sending troops into Gaza than into Lebanon. In both cases, Israel had the right to take responsive action of a defensive nature, but the right did not arise to the right of self-defense as that term of art is understood in international law. By deciding to use force of an extensive nature, including sending troops into Lebanon, Israel acted disproportionately.

Self-defense in international law is governed by United Nations Charter Article 51. Article 51 gives states the right to use force in self-defense if an armed attack occurs. This means, as the International Court of Justice clarified in its 2004 Wall advisory opinion, that a significant armed attack for which a sovereign state is legally responsible may be met with the military force necessary to defend the victim from the attacker. The defense may be taken to the territory of the attacker and the ability to attack again eliminated. The defense of Kuwait after the invasion by Iraq in 1990 is the textbook case. Pushing the Iraqi army out of Kuwait and creating a buffer zone was what was necessary to defend Kuwait. Going all the way to Baghdad was not necessary and would have involved, therefore, a disproportionate use of force.

By contrast to the Kuwait case, the case of Hamas in Gaza is much more complicated. It seems most accurate to continue to treat Gaza as an area of occupation. Palestine as a whole is not yet a sovereign state, in part because Israel is still in occupation of the West Bank. Israel pulled its settlements from Gaza but seemed to continue to exercise a sort of quasi-occupation of Gaza. Israel has the legal obligation to end its occupation, but, while the occupation continues it has the right to keep order. Thus, Israel may have had a lawful basis for responding to Hamas that included sending forces into Gaza.
The forces needed to respect the principle of proportionality in using force to respond to Hamas.

The situation is different respecting Hezbollah and Lebanon. Lebanon is a sovereign state. Under the current publicly available facts, Lebanon is not legally responsible for Hezbollah’s raid into Israel. Hezbollah’s acts were not those of a sovereign state and thus do not give rise to the right of self-defense under Article 51 of the Charter. Even if the facts later show that Lebanon was responsible, the Hezbollah raid would still not give rise to the right of self-defense. Such low-level acts of violence are considered “incidents”.

The ICJ made this point in the 1986 Nicaragua Case. The Court distinguished minor armed exchanges or “frontier incidents” from attacks that give rise to the right of self-defense.(2) In 2005, the Ethiopia-Eritrea Claims Commission found that the armed exchange between Ethiopian and Eritrean troops in the town of Badme did not give rise to the right of Eritrea to use the level of force permitted in self-defense.(3) World leaders calling Israel’s conduct disproportionate seem to be reflecting this understanding. Israel could react to the raid and the kidnapping of its two soldiers, but to launch a major assault as far as Beirut in response to this crime was disproportionate.

Subsequent to initiating force against Lebanon, Israeli leaders have stated their goal in using force was to cripple Hezbollah. This is much the same reason it gave for invading Lebanon in 1982. In 1982, however, Lebanon was in the midst of a civil war.

The country was in no condition to control events on its territory. In such a situation, Israel likely did have the right to use force in self-defense on the territory of Lebanon. When Israel advanced all the way to Beirut, however, far from the area where the attacks on it originated, it violated the principle of proportionality. This is the position that even the United States government took at the time.

Prior to Israel’s latest incursion, Lebanon was not in a civil war. No one would say it had achieved an adequate level of stability and self-government, but neither was it a situation of chaos as in 1982. It was under a Security Council mandate in Resolution 1559 to disarm Hezbollah. That needed to be done, but this failure did not mean the territorial integrity of Lebanon could lawfully be disregarded. Nor did Israel have a unilateral right to enforce the Security Council resolution.

In the Nicaragua Case, the International Court of Justice said the victim of wrongdoing in a border incident must use counter-measures in response as there is not right of self-defense. Counter-measures are otherwise unlawful acts, not involving the use of significant armed force, taken in response to a prior unlawful act as long as they are proportional to the harm caused by the wrong. The most common forms of counter-measures are economic sanctions, but the potential range is wide. For example, attempting to rescue the kidnapped soldiers would have violated Lebanon’s territorial integrity—a wrong, but Lebanon is at least guilty of a failure of due diligence regarding Hezbollah for which such a counter-measure might have been an appropriate response.

This brings us back to proportionality. Counter-measures are also governed by a principle of proportionality. The measure taken in response must be proportionate to the harm caused by the wrong. Proportionality requires assessment of the means to accomplish the lawful objective.

When states have no right to resort to force or no right to resort to force to the extent they do, the principle of proportionality governing the conduct of force still applies. Lawful targets are targets that help to achieve the military purpose of the state using force even if that purpose is unlawful. When the United States and its coalition partners invaded Iraq in 2003, for example, they had no legal right to do so. Still, we judge the proportionality of the use of force against the stated purpose of changing the regime in Iraq. It is probably the case, however, that in assessing military objectives and the proportionate use of force in achieving them, an unlawful purpose colors the assessment.

Israel’s purpose in attacking Lebanon is apparently to disable Hezbollah as a militant force. As indicated above, this purpose is arguably impermissible under the jus ad bellum. Nevertheless, we need to distinguish between targeting Hezbollah rocket sites, a lawful military objective, from targeting Beirut’s port, airport, power stations, bridges, residential areas, and the like. Even with regard to the rocket sites and stockpiles, the proportionality of the attacks must be weighed. World leaders likely had in mind this calculation but also the sense that responding to Hezbollah for the raid was justifiable; using force on a major scale to respond to another problem rendered the force used disproportionate.

Israel’s ambassador to the United Nations speaking at a pro-Israel rally responded to charges that Israel was using disproportionate force. He said, “You’re damn right we are.”(4) This statement was not only an admission that Israel has acted unlawfully, it is also a prediction that Israel is unlikely to achieve the peace its people surely desire. The principle of proportionality is one of those principles of international humanitarian law that reflects basic moral consensus and as such is linked to achievement of peace and conflict prevention.

As long ago as St. Augustine (354-430 A.D.) it has been understood that waging war in a way that respects shared understandings of acceptable conduct helps to win the peace. Augustine taught that war should always be conducted with an eye on the peace. It was with this perspective in mind that Abraham Lincoln ordered the first codification of the law of land warfare to govern the conduct of Union forces in the field. It did not matter that the Confederacy would not be abiding by those rules. What mattered for Lincoln was that the war would end and that the belligerents would be able to live together in peace. Treating the enemy proportionately, in accord with ancient principle, helped achieve that goal.



1. This analysis is drawn from Mary Ellen O'Connell, International Law and the Use of Force (2005) and Judith Gardam, Necessity, Proportionality and the Use of Force By States (2004).

2. Military and Paramilitary Activities In and Against Nicaragua (Nicaragua v. U.S.), 1986 I.C.J. 14, 102-03 (June 27) [hereinafter Nicaragua]. See also, International Incidents: The Law That Counts in World Politics (W. Michael Reisman & Andrew R. Willard eds., 1988.)

3. Eritrea-Ethiopia Claims Commission, Jus Ad Bellum (Partial Award, Dec. 19, 2005)

4. Steven Erlanger, "With Israeli Responses, a Debate Over Proportion," New York Times, July 19, 2006, at A1.

Mary Ellen O'Connell holds the Robert and Marion Short Chair in Law at the University of Notre Dame


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