Legitimacy of the use of military force is undergoing a fundamental but insufficiently appreciated moral and legal transformation. Whereas the traditional practices and laws of war defined enemy forces in terms of categorical, group-based judgments that turned on status—a person was an enemy not because of any specific actions he himself engaged in but because he was a member of an opposing military force—we are now moving to a world that, implicitly or explicitly, requires the individuation of enemy responsibility of enemy persons in order to justify the use of military force. Increasingly, the legitimate use of military force is tied to quasi-adjudicative judgments about the individual acts and roles of specific enemy figures; this is the case whether the use of force involved is military detention or targeted killing. This transformation transcends conventional debates about whether terrorist actions should be treated as acts of war or crime and is more profound in its implications.
This readjustment in the basic premises underlying the justified use of military force will have, and is already having, implications for all the institutions involved in the use of military force and in the processes by which decisions are made to use force. For the military, this change will generate pressures to create internal, quasi-adjudicative processes to ensure accurate, credible judgments about the individual responsibility of particular enemy fighters. For the executive, these changes will propel greater engagement in decisions that had previously been exclusively within the province of the military. For the courts, this transformation toward individuated judgments of responsibility will inevitably bring about a greater judicial role in assessing wartime judgments than in the past; this expansion has begun to occur already. These changes are not yet directly reflected (or at least fully reflected) in the formal laws of war, but we anticipate that as these changes embed themselves in the practices of states, especially dominant states, these changes in practice will also eventually be embodied in the legal frameworks that regulate the use of force. This Article will identify this fundamental transformation as the central factor driving struggles over the proper boundaries of military force and then explore the ramifications of this change for issues like military detention and targeted killings.