pr00ne,
Not missing the point, merely making the point that theoretically the UN Charter limits the legitimate use of force to the three cases I outlined - Self Defence, UN Security Council sanctioned action under Chapter VII, and the vexed question of humanitarian intervention.
I come down on the side of the legality of humanitarian intervention, though not uncritically. The Michael Walzer / Ian Brownlie brand of narrow positivism, and the Simon Chesterman / Thomas Franck pragmatic positivism presents a conundrum - how can the UN, a body expressly created to define and police new human rights protections in a world shocked by WWII’s horrors, deprive its members of the means to stop such abuses?
My answer is that the international community should not stand by in cases of genocide, war crimes, crimes against humanity, and if the UN is deadlocked, the UN Charter should not stand in the way of effective (military) action to stop these crimes occuring. On this basis, one finds that Kosovo was legal, whereas Suez was not. (That having been said, the manner of the Kosovo campaign does invite some valid criticisms.)
Unless you beleve that the post WW-II humanitarian treaties were purely decorative, and that no-one actually intended human rights considerations to interfere with the serious business of classical state policy driven by self interest, then you are obliged to accept that the signatories did indeed expect them to work approximately as designed.
Collective security’s failure during the Cold War does not vitiate the intent of its’ creators: instead the expectation that collective security could be invoked in support of human rights supports the notion in the rationale that human rights were important, and that where the collective security framework failed, the protection of human rights would remain a priority. If so, then the right of states to intervene to uphold them was not designed to be constrained by the UN Charter.
And yes, I agree that the A-Gs legal advice before GW2 was risible, and that the conflict was an illegal act of aggression. The problem I forsee for the (very brave) Flt Lt, is that the presence of UK forces is mandated by UNSCR 1546 and that therefore the process will be short-circuited without any serious consideration of the "crime of aggression = an illegal order" argument.
S41