I disagree a bit here. I don’t think this war is a question of legal or illegal.
I don’t think you can sum up this war in one question at all. It is a clouded and complicated iusse.
It truly is, and everyone has different emphasises of importance on different questions on that issue.
If one is going to agrue the legality of this war than one has to say that action in Kosovo was illegal and should not have been done. The UN, as a body, did not approve it. However, the question is was it the right thing to do? I would think yes.
But the situation was different: First it was NATO going in, second the UN later de facto approved the action.