Put that way it sounds silly. I mean isn’t ISIS simply IN various parts of Iraq and Syria and wouldn’t US involvement in something like an all out attack on ISIS mean intervening in any number of civil wars? Well that depends on how smart your lawyers are (and I am only kind of smart and not a lawyer at all). But let me float a trial balloon (one fully equiped with Hellfire Missiles and Special Forces assault teams).
One. There is such a thing as the self-proclaimed Islamic State. And this sovereign state does have existing if fluid borders, that is there are parts of the territory of pre-existing states like Iraq and Syria that are now not under the physical and military and administrative control of those states. To that degree there is in fact an independent territorial based Islamic State. Moreover this IS has in very explicit fashion declared war on the United States, most recently be executing a U.S. citizen and threatening the same against his compatriot.
Which leads to this perhaps counterintuitive suggestion. Declare war on ISIS while simply allowing any territory gained in that military effort to simply be reabsorbed by the former state actors who held it. That is simply regarding any territory held by ISIS to not actually be in Iraq or Syria while allowing any and all claims to territory liberated from ISIS to revert to the states which formerly and still formally claim it. And this latter move could be itself justified by simply refusing to commit ‘boots on the ground’ to actually taking that territory as opposed to the deployment of targeted ground assaults within the territory currently controlled by the Islamic State. That is the U.S. would commit to the destruction and dismemberment of the IS while not formally taking control of any part of it. And by that token never actually waging war in ‘Iraq’ OR ‘Syria’.
Maybe this is too clever by half to be workable. But what it would conceptually do is convert ISIS into the Cheshire Cat state, simply vanishing as every piece of it is dismantled around it. Leaving nothing but the dream of a Caliphate (and being realistic an ongoing terroristic threat to both the restored Iraqi and Syrian States and the West at large).
The main conceptual difference between this effort and the Second Iraq War is that the U.S. by and large wouldn’t own the Pottery Barn where the breakage occured. Because by donning the proper set of logical blinders we could make the case that we weren’t ‘really’ engaged in war on current Iraqi or Syrian soil. And if those state actors had a beef with us waging war on what they consider to be their sovereign territory the U.S. answer would be simple: “Okay take back that territory an inch and a mile at a time and raise your own flag over the liberated cities and villages”. Because if that village or region or province is no longer under IS control it would not be at war with the U.S. And as such there would perhaps not ever be such a thing as the “U.S. Occupation of the Islamic State”.
I am not saying there would not be complications. After all the dissolution of the Ottoman Empire after WWI delivered us right into WWII via the new Balkan States and even more so into the current I-P mess verging on horror, the ‘War to End All Wars’ is maybe the most ironic slogan ever invented. Still it is clear that the U.S. needs to put paid to ISIS while having some plausible deniability of actually occupying parts of war torn Iraq and Syria. And simply defining the Islamic State as being such and so a proper and plausible target of a Constitutional Declaration of War seems a reasonable way of slicing the logical knot here.