Can you equate international law norms regarding collective security policy (UN authorization for use of force) and warfighting norms (on using human shields), as Kinsley apparently has? I think not.
And he answers with a mix of hardcore polisci-speak and successful folksiness:
There is a great amount of flexibility at the macro level of international law because of the fundamental anarchy of the post-Westphalian system of sovereign states. While sovereignty has been eroded somewhat, superpowers still get to play the way Michael Jordan played basketball.
(We might call this the interplay between the post-Westphalian and the Paul Westphalian. …)
There is a general consensus in the Fray about human shields, exemplified by J_Mann here:
I actually don't think that voluntary human shields raise any war crimes by any side. If these men and women put themselves in harm's way in an effort to influence the outcome of a war, then as far as I'm concerned, they're not civilians, they're something a lot closer to combatants. We shouldn't deliberately target (or prosecute) them because they don't represent any military threat to them, but I don't see why we (or Saddam) should worry too much about a bunch of people who intentionally put themselves in harm's way.
(Also, if we haven't infiltrated the shields with spies, we're missing a great chance).
There is more to J_Mann's post, and DeaH has more to say about shield spies here.
When it comes to multilateralism, the most pointed warrant for waiting for the UN comes from DavidInnes-3 here:
To put it bluntly I'd like to see the U.N. on board because, unlike the Bush family and their coven of loyal retainers, the U.N. has a record of following up so that another fucking mess doesn't boil up again in a couple of years.