Professor Yoram Dinstein has characterized war as something that would “appear every once in a while, leave death and devastation in its wake, and temporarily pass away to return at a later date.” While that’s truer for some countries than others, when it comes to the United States, President Obama’s speech last Wednesday made it clear that he’s determined to prove the wise professor wrong.

This brings me to a post on Just Security by Professor Michael Lewis, who offered an understanding of the “unwilling and unable” test that I believe advances a legal interpretation that makes war more permissible than what international law intended.

Michael was responding to Ryan’s post on how international law regulates the use of force by the United States against a non-state actor (ISIS) in a foreign state (Syria). In a nutshell, Michael took issue with Ryan’s assertion that if Syria offered its cooperation to the United States (which it did), then the United States would have to take that offer seriously before claiming a right to self-defense. Michael, disagreeing, said this “would effectively give Syria a measure of control over US targeting decisions on its territory.” As Michael understands it, “the US position is that the phrase ‘unable or unwilling’ describes the host/target state’s capacity to control its own territory,” which Michael said Syria is incapable of doing. Thus, if Syria doesn’t have territorial control, then it’s unable to suppress the threat, and therefore the United States can invoke the principle of self-defense.

This is where I disagree with Michael, and where I see his interpretation of the “unwilling/unable” test to be one of those legal interpretations of international law that would allow the United States to be in a “forever war.” Specifically, my objection is with Michael’s emphasis on a “state’s capacity to control its own territory.”

If the United States thinks it can suppress the threat of ISIS in a territory that it does not control, why should Syria’s inability to control that same territory necessarily mean that it too could not suppress the same threat? And, if Syria could suppress the same threat without territorial control, then why should Syria lose its sovereign rights? Michael’s logic simply doesn’t work for me. I’ll concede that my questions might get a bit more hairy if we talk about detention operations, instead of airstrikes, as a means of suppressing a threat. In detention operations territorial control may (may) be a more determining factor. But the fact that different scenarios alter the terms of the unwilling/unable test goes to my main point: What is needed is a fact-based test that considers both the threat and Syria’s ability to deal with the threat, not a generalized rule that hinges on territorial control.

I also find it difficult to accept Michael’s interpretation of the “unwilling/unable” standard—a standard which Ryan correctly notes is “a fairly well settled part of the US government’s legal position [but] remains controversial under international law”—because a state’s unwillingness or inability to act is not fixed or etched in stone, especially when that state becomes informed that its unwillingness/inability may result in heavy diplomatic consequences or, at the extreme end of the spectrum, a foreign power attacking its territory. One day a state may say it is unable or unwilling to act, but the next day may be different. This could be due to competing internal versus external politics, or the availability of resources. My point is that things can change. What Michael offers, however, seems to be too static and is effectively an end-run around the “unwilling/unable” test rather than approaching it as a complex and dynamic standard that has the function of ensuring that a state is appropriately balancing its national interests with the sovereignty of other states.

If you think of all the places in the world where states don’t have control over parts of their territory, you can quickly start to see how Michael’s understanding of the “unwilling/unable” test threatens to unravel the principle of sovereignty. Such breaches of sovereignty would be nearly always justifiable, if not encouraged. It’s also important to ask: Would the territorial states simply stand by without a response, violent or otherwise? Michael’s proposed solution—while no doubt intended to be in the interest of U.S. security—would open a Pandora’s box, be it now or later, for the United States, its allies, and many others.

In contrast to Michael, I see Ryan’s position as better serving to keep a state in the “consent/cooperation” paradigm for as long as possible—no matter how politically unsavory that may be—before letting a state hit international law’s red button. If Ryan is correct on this point, and I think he is, then Syrian offers of cooperation slow down how quickly the United States can pass through the unwilling/unable “window” into the world of self-defense. Until the issue of cooperation is resolved (which Ryan discusses here in his response to Michael), the United States must remain in the world of consent-based use of extraterritorial force (or obtain UNSC authority). This being the case, Syria certainly has a say in what the United States may or may not do on its territory.

This reality, however, raises a host of questions, such as what if the territorial state only cooperates or lets the United States take action in limited ways that the United States does not see as producing a satisfactory response? What if, for example, the territorial state says it will arrest the threat, but the United States has no faith in the justice system and says that the only acceptable solution is for the United States to kill or capture the threat? And what if the territorial state’s domestic laws don’t permit this? What then?

I have no neat answers, other than to say that these issues are especially complicated but often ignored due, perhaps in part, to the United States’ elongated concept of imminence. If you accept the United States’ expanded definition of imminence, then you also have to accept that the United States is permitted to act immediately or with considerable force against an uncertain threat, even when the territorial state determines that it can, and will, address the problem only by acting more slowly, or with less force. At worst, Michael’s understanding of the unwilling/unable test, matched with “elongated imminence,” sets the stage for states not even having to think about asking the territorial state if they are able to suppress the threat.