1. The accepted legality of cluster weapons
Both international law and accepted practice do not prohibit the use of the family of weapons popularly known as ‘cluster bombs’. Consequently, the main issue in a discussion of Israel's use of such weaponry should be the method of their use, rather than their legality.
A 2002 report by Human Rights Watch on explosive sub-munitions - the category of weapons to which cluster bombs belong - states that these weapons are stocked by 56 countries and have been used by at least nine (including the US, Britain, Russia, and Israel). There are 208 types of sub-munitions, which are manufactured by 33 countries. The US used cluster bombs during the Gulf War, as did NATO forces in Serbia and Kosovo.
One of the arguments used by those who support the use of cluster bombs is that this weapon causes in most cases less damage than that caused by a regular (250-1,000 kg) bomb.
2. The legal method of use
It goes without saying that any use of weapons in warfare must comply with the international laws of armed conflict concerning legitimate targets (the principle of distinction between combatants and civilians), avoidance of deliberately harming civilians, the principle of proportionality, and the need to take reasonable care. In addition, it is prohibited to use weapons that cause superfluous injury or unnecessary suffering, and weapons that are inherently indiscriminate.
When examining the legality of an attack on a legitimate military target, additional parameters may also be examined, such as the extent of incidental injury to the civilian population in the vicinity of the target and the military advantage achieved in attacking the target. The balance between the two determines the legality of the entire attack.
3. Israel’s use of weapons in compliance with international law
These considerations of compliance with international norms were paramount features of the Israel Defense Forces’ (IDF) operations in Lebanon, in which strenuous efforts were made to ensure that these were carried out in complete accordance with international law, both with regard to method and weaponry.
IDF operations are directed only against legitimate military targets (the terrorists themselves, the places from which they launch attacks against Israel, facilities serving the terrorists, and objectives that directly contribute to the enemy's war effort).
The IDF does not deliberately attack civilians and takes steps to minimize any incidental collateral harm by warning them in advance of an action, even at the expense of losing the element of surprise. This measure, which is not obligated by international law, proved itself in practice by in fact reducing injury to civilians.
4. Hizbullah use of civilians as human shields
This concern for civilian welfare points out one of the clearest distinctions between the IDF and a terrorist organization such as Hizbullah, which cynically exploited Israel's humane practice by deliberately operating among civilians, using them as human shields by storing and even firing missiles from inside their homes.
The use of human shields is banned by international law, which states that hiding a terrorist objective in the heart of a civilian population does not afford it immunity against attack.
5. Clean-Up efforts after hostilities
On conclusion of hostilities, questions arise from both sides regarding unexploded ordnance left behind on the battlefield. For example, many deadly explosives fired by Hizbullah against northern Israeli population centers still remain unexploded. Israeli civil defense authorities are consequently making great efforts to locate and disarm these weapons in order to protect Israeli civilians from further harm. Israel regards the welfare of Lebanese civilians in same manner. Immediately after the cease-fire the IDF gave UNIFIL maps indicating the likely locations of unexploded ordnance, to aid the international attempt to clear these areas and avoid injury to the population. Furthermore, immediately after the cease-fire the IDF distributed warning notices to the residents in the areas of warfare, and recommended that they wait a few days before returning to the south until the UNIFIL forces were deployed there and the area had been cleared of unexploded ordnance.