Even if we suppose that the empirical claims hold (and I"m not sure they do), I have no idea how the concept of a "failed state" is supposed to bridge the gap between "these governments are having a hard time keeping control" and "these governments don't really exist and their people can be bombed at will".
I think the bridge is supposed to be here:
Failed states in general, and particularly those in the Middle East, represent potential threats to the US because they could be transformed into terrorist bases. Those failed states that have already become terrorist bases, have clearly moved from potential threats to emerging ones, and thus the administration's fundamental national security strategy requires that it act forcefully in order to head off such threats.But, of course, that someone is potentially dangerous (not actually, but potentially) doesn't justify doing whatever the hell you want in response. So, really, it has to be the concept of a "failed state" -- some sort of moral black hole, in which conventional (let alone ideal) normative standards do not apply.
It's the most vile idea I've run across in a while. (The author, for those who are wondering, is Dr. Nadav Morag, a political scientist and the University of Judaism in Bel Air, CA, who has worked as a policy advisor for Israel. So, he's a little biased. I'm surprised he's such a neocon hawk, though.)