The Killing of Fazul Abdullah Mohammed and the Issue of Organizational Indeterminacy Under the AUMF

The killing of Fazul Abdullah Mohammed by Somalian soldiers this weekend provides yet another occasion to note the difficult scope issues that arise under the 9/18/01 AUMF (or, if you prefer, under the President's Article II authority to use force to defend the nation against al Qaeda).  Mohammed is most notorious for his role as mastermind of the 1998 East African Embassy Bombings, and has been linked to various other al Qaeda plots over the years.  At the same time, he has more recently become part of al Shabab's leadership as well.   As the New York Times story on his killing explains:  

He wore two hats, officials said, as the leader of Al Qaeda’s franchise in East Africa and a top field commander for the Shabab, the Somali militant group that started as a homegrown insurgency but has steadily drawn closer to Al Qaeda and expanded its ambitions, carrying out a suicide attack in Uganda last summer that killed dozens.

Mohammed's "dual-hatted" status no doubt was one part of an argument that could be made for categorizing al Shabab as part-and-parcel of al Qaeda and hence within the scope of the AUMF/Article II, without regard to the merits of a stand-alone argument about the propriety of using force against al-Shabab based soley on its own activities.  The more personnel overlap there is between them, of course, the easier it is to make that case.  More difficult questions arise if and when there are no figures such as Mohammed left to blur the distinction between the two groups.  At that point, the argument would have to depend on difficulty-to-ascertain indicia of cooperation or command-and-control between the group.  And that, in turn, draws our attention to the lack clear legal metrics for determining when two entities are sufficiently related to count as one for this purpose.    I am not sure whether this particular form of indeterminacy could be addressed legislatively.  Don't misunderstand me; obviously legislation could skip over the issue by just explicitly authorizing the use of force against al Shabab.  I just mean that it is unclear to me whether it is possible to craft a generic legislative standard for organizational relationships that would provide an administrable metric for determining whether and when a group such as al Shabab counts as part-and-parcel of al Qaeda.  For years the US government has used the rubric of "associated forces" to get at this idea, and this is the approach carried forward in the House version of the NDAA FY12.  It seems to me that that rubric is more of a label for the issue rather than a solution to it, but again I'm not sure just what an actual solution would look like.  Perhaps one is not needed; I'm sure the government would prefer to have the flexibility that flows from the indeterminacy, at least so long as the indeterminacy is not coming back to bite it through strict judicial interpretations in habeas litigation....