Nó cũng cần thiết để cho thấy rằng các biện pháp liên quan đến "không có gì bất hợp lý hoặc quá mức, kể từ khi hành động chứng minh bằng sự cần thiết phải tự vệ, phải được giới hạn bởi sự cần thiết đó, và được ghi rõ ràng bên trong nó. | self-preservation necessity self-defense 333 leaving no choice of means and no moment for deliberation. It was also necessary to show that the measures taken involved 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. 30 The principle of necessity means that no other peaceful alternative measures are available or effective. Use of force was to be a measure of last This operates as the functional equivalent of ordinary law first in the derogation regime s use of the proportionality test. Equally the principle of proportionality was considered to be the crux of the self-defense doctrine in international law. A third condition which forms part of customary international law on this matter is the principle of immediacy. This principle requires that there will not be an undue time-lag between the armed attack and the exercise of self-defence. 32 Thus if the historical model of self-preservation ushered in an element of extralegality the doctrine of self-defense was part and parcel of a model of accommodation internalizing rules concerning use of force into the system of international law and operating within the legal framework of international law rather than outside it. This conceptual distinction which had been mostly theoretical during the nineteenth century when war was not legally outlawed became significant with the prohibition on war and use of force. In modern form this prohibition is most cogently and authoritatively expressed in article 2 4 of the United Nations Charter UN Charter which provides the general rule prohibiting the use of force in inter-state This general prohibitory rule is subject in turn to article 51 of the charter which permits a resort to individual and collective self-defense in certain circumstances as well as to the power of the Security Council to authorize the use of force under Chapter VII of the charter. A .
