So, as David Cameron says, “the action has the full and unambiguous legal authority of the United Nations”.
The thing is (and never mind exactly how one defines “occupation” and “civilians”): who decides which measures do and don’t count as “necessary”? In practice, the governments taking those measures get to make those calls. One couldn’t rule on every possible path through the fog of war in advance, and there’ll be no UN tribunal at the end of it to assess every bomb dropped. So, in reality, “unambiguous legal authority” blurs into what the governments think they can make plausible. Bombing tanks outside Benghazi? Taking out air force bases? Destroying a government compound in Tripoli? Killing Gaddafi?
What is Cameron’s rationale in establishing what’s necessary? This:
Targets must be fully consistent with the UN Security Council resolution. We therefore choose our targets to stop attacks on civilians and to implement the no-fly zone, but we should not give a running commentary on targeting and I do not propose to say any more on the subject than that.
(And just look at this poor wretch of a Foreign Office minister getting Paxmanned [from about 27’00].)
There’s something of a Humpty Dumpty-ish “it means just what I choose it to mean” quality to this. While bombings and raids are ongoing, Cameron will often refuse to elaborate, implicitly demanding our trust. More broadly, he’ll come up with whatever justifications are needed to maintain a sense of legitimacy about this campaign. Every war leader does this.
International law is a morass of grey areas. In the end, the only authority that will matter to him is moral authority, as defined partly by him and partly by public opinion.
But I hope it works. I hope the cost in lives is minimal. I hope Gaddafi is deposed quickly; given the coverage of the amateurish-looking rebels, it appears that the likeliest way for that to happen is for the army leadership to turn against him. And I hope the successor regime is benevolent.
If I have to be on one side of the fence, then I’ll come down in favour: with no military intervention, Gaddafi would have finished crushing the rebellion and then redoubled his repression. As it is, some other series of events will happen. In the short term, things will be better (or less bad); in the long term, nobody knows. But I hope people smarter than me are thinking hard about it.