The 2001 AUMF: From Associated Forces to (Disassociated) Successor Forces

Like my colleagues Ben and Wells, I'm astonished to learn this evening that the Obama administration, having previously justified 140+ airstrikes against IS in Iraq on Article II grounds alone (at least insofar as the stream of WPR reports indicated), has discovered that IS all along was covered by an AUMF...and not the 2002 AUMF relating to Iraq, but the 2001 AUMF relating to al Qaeda. To be sure, there was a time when this would have been a perfectly fine argument; IS is the descendant of AQI, after all, and for many years it would be easy to show that AQI was an associated force of AQ engaged in hostilities against the US. But so far as I know no one seriously denies that it has since had a fundamental rupture with AQ, and indeed engages in combat at times with AQ's Syrian outfit, the al Nusrah Front. For the administration to claim, as Marty Lederman reports here, that IS nonetheless remains subject to the 2001 AUMF both because of this past and because IS though now independent in some fashion claims to be the "true inheritor" of "bin Laden's legacy" (and because AQAP and other AQ associated forces have made ambiguous statements, for whatever reason, applauding IS's claims and achievements) is just stunning from a legal perspective. To be clear, I'm not driven to this argument out of hostility to the policy the President described this evening; on the contrary, I'm cautiously supportive. It's just that I think the legal arguments really do matter, or at least that they should. Until this evening the big AUMF interpretive boundary seemed to be the notion that it extended only to AQ's associated forces actually engaged in hostilities against the United States (though the recent al Shabaab strike perhaps shows this line was not so important after all?). Now we are speaking not just of "associated forces," but also "disassociated forces" that might, from a certain point of view, be seen as "successor forces." Will we later hear of the AUMF applying to associated forces of this successor force? It is not hard to imagine many of them popping up the Iraqi-Syrian theater. To be sure, the White House isn't saying the AUMF covers just any group. There is still a thread of AQ connection in the IS fact pattern, after all, thanks to IS's specific history as AQI. But if a past nexus is now all that is required, the door may be opened to applying the AUMF to any situation in which members of some new entity have substantial prior ties to AQ or an AQ associated force. Given the sprawling social network that undergirds the larger salafist jihadi movement, and the constant froth of new groups and entities that movement produces (often building from the remains of earlier groups and entities), this is a somewhat daunting prospect, at least if you would prefer to see the use of force against such targets resting on a clear domestic law foundation.