 As you may remember, article 51 says nothing about the author of the armed attack. It simply refers to the following hypothesis, if an armed attack occurs. Article 51 does not say by whom armed attack occurs. As I made clear earlier, this is not a surprise because at the time the charter was drafted, only states were carrying out armed attacks. During the attacks of 9-11, the Security Council adopted Resolution 1368 and 1373. The preambles of those resolutions explicitly reaffirmed the inherent right of individual or collective self-defense. And this seems to suggest that self-defense is triggered by attacks carried out by terrorist groups. However, in the whole advisory opinion, the International Court of Justice seemed to disagree with such conclusion. The court examined whether the construction of the wall by Israel in the Palestinian-occupied territory could be justified on the basis of self-defense. And the court said this, I quote. Article 51 of the charter recognizes the existence of an inherent right of self-defense in the case of an armed attack by one state against another state. However, Israel does not claim that the attacks against it are imputable to a foreign state. End of quote. And furthermore, you may remember that in the Kosovo advisory opinion, the court said that the principle of territorial integrity, which is protected by the prohibition to use force under Article 2, paragraph 4 of the charter, that this principle is, I quote, confined to the spheres of relations between states. Because Article 51 is an exception to Article 2, paragraph 4, this reinforces the idea that self-defense is only applicable between states. And does that mean that states may never use force in self-defense against terrorist groups that are based abroad when those groups have carried out an armed attack? Well, I don't think so, and let me explain why the whole opinion should not be understood as forbidding self-defense against terrorist groups acting from abroad. Well, immediately after having recalled that the inherent right of self-defense is recognized in the case of armed attack by one state against another state, immediately after that, the court noted that Israel exercises control in the occupied Palestinian territory. And that by building the wall, Israel intends to protect itself from a threat coming from that territory it controls. The occupied Palestinian territory where, according to Israel, the terrorist groups are present is a foreign territory. But Israel is present on that territory, and it is in control of that territory. So said the court, the situation is different from the situation dealt with by the city council in the aftermath of 9-11. Because Israel controls and occupies the Palestinian territory, there is no real issue of using force abroad in self-defense. Israel is an occupying power and can only use force as an occupying power under the relevant rules of the use in Bello. Therefore, the dictum I refer to above is not to be understood as meaning that self-defense is only possible in case of an armed attack by one state against another state. A state-to-state situation is, of course, one situation in which self-defense applies. But it is not the only situation in which it is possible to use force in self-defense. And this is indeed the view of the Institute of International Law, of which many ICJ judges are members. According to the Institute, I quote, in the event of an armed attack against a state by non-state actors, Article 51 of the Charter as supplemented by Castro International Law applies as a matter of principle, end of quote. So using force in self-defense against a terrorist group acting from abroad is, in my opinion, possible. The terrorist group can be the target of self-defense military operations. But the real issue is to know where to use force, where to direct the military operations against the terrorist group. And as the Institute of International Law made clear, if the terrorist group is present in an area beyond the jurisdiction of any state, if it is, for instance, on board a ship on the high seas, well, there is no doubt that the state victim of the terrorist armed attack may use force in self-defense and destroy the boat where the terrorists are present. However, most of the time, terrorists are not at sea, but on the territory of a foreign state. And that state must cooperate with the victim state, and it should take the law enforcement measures against the terrorist group, which is present on its territory. The foreign state where the terrorists are hiding could also consent to a foreign intervention, and there is no need to speak of self-defense in such a case. But watch if the foreign state refrains from doing anything. If the state where the terrorist group is present is unwilling or unable to take the appropriate measures against the terrorist group, the following question will arise. Is the victim state entitled to use force in self-defense on the territory of that foreign state, not using force against that foreign state, but using force on that foreign state territory against the terrorist group? And that is really the core question. It is a very controversial question, and it is easy to understand why it is controversial. And it is also easy to figure out the respective legal positions and arguments of the various states involved. One practice is in a flux, and it is probably too soon to definitely assess the status of the law in that regard. And doubtedly the behavior of the territorial state where the terrorist group is hiding will be a crucial factual element. Likewise, the actual necessity of going after the terrorists in terms of protecting the victim state and the proportionality of the military reaction will also be of crucial importance. And those elements have to be assessed on a case-by-case basis.