Should Detention Based on Non-Member Material Support Be Reconceived in Terms of Security Internment?

As Ben notes below, Steve Vladeck objects to the Circuit's recent ruling in Hatim insofar as that decision suggests that the Circuit has held that detention may be predicated on provision of material support to an AUMF-covered group, as opposed to predicating it on membership in such a group.  Steve's argument is that the Circuit's statements on this issue have all been dicta, and that extension of detention authority to the non-member support scenario would violate IHL.  I think Steve is right that the Circuit's statements thusfar have been dicta, but I think the IHL issue is more complicated. Steve observes that the mere provision of support by a non-member to an armed group would not traditionally be thought to render that person a belligerent.  I think that's probably correct.  But it does not follow that IHL provides no authority to detain such persons without criminal charge.  In the context of international armed conflict, the Fourth Geneva Convention permits the internment of protected persons (i.e., civilians subject to the Fourth Convention's full range of protections) where the detaining state deems this to be necessary for security reasons--reasons that certainly might include the purposefull provision of support to an organized armed group.  And as Ryan Goodman argued in an important paper in AJIL, the same may be true in a non-international armed conflict setting insofar as IHL in that context imposes fewer rather than greater constraints on the detaining power.  On that theory, the two-prong detention model described in al Bihani and Hatim (i.e., the notion that the AUMF permits detention not just of members but also non-member supporters of AUMF-covered groups) might well be best understood as resting on two distinct IHL foundations. First, the actual members of AUMF-covered organized armed groups could be detained as belligerents (subject to detention for the duration of hostilities).  Second, the non-member supporters of such groups could be held as security internees (for so long as they continue to pose a threat, subject to semi-annual review, by analogy to the Fourth Convention framework).  I'm not suggesting that the US government actually has argued this approach vis-a-vis GTMO (though I think it *very* interesting that the Fourth Convention security internment framework for years was the foundation (by analogy) for large-scale detention operations in Iraq-see this paper for the details).  Nor am I trying to open the debate regarding whether and to what extent there is an underlying armed conflict warranting resort to such concepts in a particular case; obviously that continues to be a hotly disputed issue at least for non-Afghanistan captures.  But if and when a GTMO habeas case truly compels the judiciary to decide whether non-member supporters may be detained under the AUMF consistent with IHL, I think it will be necessary to address this neglected line of argument.