The six questions posed in relation to the terrorist attacks of September 11 raise in turn a number of issues, including (a) the proper scope of the right of self-defense under contemporary international law and (b) the limitations on aerial bombardment under contemporary international law. Due to limitations of space I can only touch upon them briefly in the course of responding to the questions posed.

The attacks of September 11 were barbaric acts. However, to characterize them as "acts of war" would not be appropriate in the accepted idiom of international law. After the adoption of the UN Charter, formal resort to "war" is no longer an available option, as the Charter restricts the use of armed force by States. Armed force can be used only by authorization of the Security Council¹, or in exercise of the inherent right of individual and collective self-defense under article 51 of the Charter.

The September 11 attacks fly in the face of the provisions of various international conventions and resolutions of the United Nations on terrorism, crimes on board aircraft, etc. To cite an example, the Hague Convention of 16 December, 1970, makes the hijacking of aircraft an international crime, and each Contracting State is required to make the offence punishable by imposing severe penalties.

If the attacks of September 11 are attributable only to terrorist cells or groups comprising private individuals, then these acts would more appropriately be considered as "crimes" under the relevant municipal law; and U.S. domestic law would no doubt afford ample jurisdiction to deal with the perpetrators, when apprehended. Though the actual hijackers have perished, the plotters and planners are still around.

On the other hand, if the September 11 attacks can be attributed to, or imputed to, a State (e.g. Afghanistan), then it can be contended that the international responsibility of that State is attracted. In such a context, the attacks of September 11 could be considered as "acts of aggression" against the United States.

A point to be noted is that we are really talking here of a regime (the Taliban regime), which is virtually unrecognized by the international community. However, it controls a substantial area of Afghanistan in which terrorist cells and camps are located.

When President Bush and others in the U.S. administration spoke of "acts of war", I believe they were not intending to use the term in a technical, legal, sense. It was obviously part of an effort to convey to the general public the nature of the challenge the country faced and which would have to be dealt with on a "war" footing, in a non-technical sense.

The legal limitations on a U.S. response turn upon our understanding of the proper scope of the right of self-defense. There is more than one school of thought, with some holding that the right of self-defense should be restrictively interpreted and confined to repelling an armed attack. Remedies against the aggressor should be sought through the institutional mechanism of the United Nations. However, there is also a substantial body of opinion tending to hold that if a State is aware that (further) acts of aggression against it are being planned, which may have disastrous consequences for it, then it cannot be expected to wait for such (further) attacks to occur, especially given the known inability of the Security Council to act decisively, effectively, and in good time. States acting in self-defense will doubtless take note of the criteria of necessity and proportionality, reiterated by the International Court of Justice most recently in its advisory opinion of 8 July, 1996, concerning the Legality of the Threat or Use of Nuclear Weapons.

Technological advances in the available means of waging "war" or launching terrorist attacks would seem to make it impractical for a State to wait until devastating attacks are actually launched on it. At the same time, however, this cannot be an excuse for an aggressor to cover up its unlawful activity by pleading self-defense. There is a dilemma here.

The Security Council, by its resolutions 1368 of 12 September, 2001 and 1373 of 28 September, 2001 has roundly condemned the acts of terrorism of September 11 against the United States and has reaffirmed the right of individual and collective self-defense, as also the "need to combat, by all means, in accordance with the Charter of the United Nations, threats to international peace and security caused by terrorist acts."²

The United States has apprised the Council of the steps it has taken and proposes to take to deal with threat it faces. If the Council, in its wisdom, does not object to the steps proposed (and since taken) by the United States, then within the institutional framework of the Charter for the maintenance of international peace and security, the United States must be deemed to have the acquiescence of the Security Council in its course of action. The same considerations would apply, by and large, to a non-UN international response, e.g. action through NATO in defense of one of its members.

We may also factor in here a further element. The United States has the support and approval of a very large number of UN member States in its response to the terrorist acts or acts of aggression on it. This represents a wider "community" interest of States in dealing with terrorism.

A separate issue is that of the application of the law of armed conflict or IHL to the use of force by the United States. Obviously, the contemporary law of armed conflict would apply to military action now being taken by the United States in and over the territory of Afghanistan. Lack of space prevents full discussion of this issue but an important question, as mentioned earlier, is that of legal limitations on aerial bombardment. Developments in the use of air power from the Second World War onwards through subsequent armed conflicts indicate that the legal limitations on aerial bombardment are becoming tenuous. Nevertheless, customary international law on the subject as represented by the Geneva Conventions of 1949 and the Protocol of 1977 do provide some protection for civilians, including their means of sustenance. Thus, Protocol I (1977) Additional to the Geneva Conventions of 12 August, 1949 provides inter alia in article 54 that no action should be taken against objects indispensable to the survival of the civilian population, such as e.g. foodstuffs, agricultural areas for the production of foodstuffs, crops, livestock, drinking water installations and supplies, and irrigation works "for the specific purpose of denying them for their sustenance value". No such action should be taken if it "may be expected to leave the civilian population with such inadequate food or water as to cause its starvation or force its movement." It is not contended, of course, that the United States is targeting objects indispensable to the survival of the civilian population; the stated purpose of the bombardment is to target only military objectives, including al-Qaeda bases. However, given the meager subsistence level of the Afghan civilian population, even collateral damage to civilian infrastructure may lead to unintended grave results. The United States has no doubt taken account of this.

"Reprisals" constitute steps taken (which would otherwise be illegal) in order to deal with earlier illegal acts committed by another State. Armed or belligerent reprisals would be legal only if they can be properly subsumed under the rubric of self-defense. The terms "retaliation" and "revenge" are not pertinent here.

The Statute of the Rome Court is not yet in force and, as its jurisdiction is only prospective, one cannot envisage a role for it. The other, ad hoc , tribunals such as those for the former Yugoslavia and for Rwanda obviously also would not have jurisdiction. The question whether a separate ad hoc tribunal should be set up in the present case is problematic at this stage. The matter is best considered, if necessary, later.