Your point about the Select commitee report is taken, and it may well be that the Nato actions in the Balkans were "illegal".
However my point is not whether security council veto by Russia, China, and (I think it was Sudan), makes something legal, or illegal.
My question is, faced with the choice, should one do the legal thing, or the right thing.
I think the right thing every time, especially in the circumstances at the time in the Balkans.
Your problem with a written constitution is that it is inflexible. Supposing something comes up which has not been forseen, then you are rendered helpless.
Suppose someone, on behalf of some foreign state, detonates a small nuclear device in New York. From intercepts your people know who did it, but from a legal point of view, the evidence is ruled out by some judge under some constitutionally provided loophole. Your lawyers can’t prove it, and Russia and China veto action in the security council.
See what I mean. Your Constitution, and UN approval is a double edged sword.