Very interesting analysis. The central legal principle that we are talking about here is under the UN Charter which of course all members of the UN agree to abi

Very interesting analysis. The central legal principle that we are talking about here is under the UN Charter which of course all members of the UN agree to abide by. Article 2(4) provides that all members will refrain from the use of force against the territorial integrity of any state. I think the question narrowly put is whether the cyber attack is equivalent to a physical attack. In this case, I think you could argue that the Stuxnet worm, at least to my knowledge, had an effect broadly equivalent to a physical attack, say by planes akin to the previous Israeli sortie against Iraq's reactor. Anticipatory self-defence is a developing topic but I don't think in this case, and borrowing from general self-defence principles, I don't think the threat was imminent enough, particularly in light of Iranian hyperbole. Of course, the reality of what would actually happen in the case of a breach would still be subject to the desires of individual countries, particularly on the UN Security Council, but for me it is still interesting to assess whether a cyber-attack would constitute a breach of Art 2(4).