同時多発テロに対する報復戦争の国際法的な正当性は成り立たない（英文）
In terms of international law, there is no legitimacy for wars of retaliation against the recent terrorist attacks.
1. A conflict becomes recognized as a "war" from the perspective of international law not simply when military actions are taken, but when a sovereign state or a guerrilla group expresses its intention to wage a war. Therefore, the recent terrorist attacks would be recognized as crimes, not as a war. Thus, the recent incidents should be treated as crimes. (source:TREATY FOR THE RENUNCIATION OF WAR AS AN INSTRUMENT OF NATIONAL POLICY 1929）
2. International law makes it clear that efforts for peaceful resolution should be made first to deal with any disputes. Since President Bush has not demonstrated efforts to resolve any possibility of future occurrences of the terrorist attacks in peaceful way, new military actions are not legitimate. (source:CHARTER OF THE UNITED NATIONS Art.2(3),Art.33）
3. International law does not recognize the legitimacy of wars of retaliation. Therefore, even if the terrorist attack this time signifies a beginning of a war, retaliation cannot be allowed unless the terrorists continue their attacks. (source:CHARTER OF THE UNITED NATIONS Art.51）
4. In order for a war of retaliation against the recent terrorist attacks to be recognized as legitimately exercising the right of self-defense, it must be waged against existing and obvious illegal actions. Preventive self-defense is not accepted by either international law or domestic law. Therefore, a war of retaliation against the terrorist attacks is not accepted as a legitimate act of self-defense.(source:CHARTER OF THE UNITED NATIONS Art.51）
5. The de fact principles of international law imply that there is no obligation for one state to hand over criminals to another state unless an agreement to do so has been concluded between the two states. President Bush's argument that military force will be used if the criminals are not handed over is itself in violation of international law. (source:CHARTER OF THE UNITED NATIONS Art.2(4)）
For the reasons stated above, I conclude that a war of retaliation against the terrorist attacks is not legitimate under international law.
September 19, 2001
（transl.by Junko Edahiro [junko@e.email.ne.jp]）