The threats of transnational terrorist networks in recent years have prompted calls for reexamining the law of war and its application to non-state entities. (1) The challenge of fitting counterterrorist operations--and the acts of terroristic individuals or entities themselves--into existing legal frameworks predates the September 11, 2001 attacks, (2) but the globe-spanning nature of the al Qaeda threat has raised the level of complexity and the stakes involved. Some states, forced to act quickly to respond to twenty-first century escalation of attacks and meet emerging threats, have struggled to fit their actions into the international law of armed conflict. (3) Legal academics have embraced this challenge as well. Some have considered the question in view of the nature and purposes of the international law of armed conflict, (4) while others have emphasized broader changes in the international order. (5)
Most legal debate has focused on the degree to which transnational terrorism does or does not resemble military and national security threats posed by state or localized guerrilla armies. Proponents of applying the law of armed conflict argue that modern terrorist organizations wage violence at a magnitude or sophistication previously achievable only by states or within local areas. Proponents of adapting the law of armed conflict argue that its basic principles fit contemporary circumstances reasonably well but that its specific rules should be modified. Opponents of adapting the law of armed conflict counter that the traditional law of armed conflict is adequate to regulate the use of force against terrorist organizations and fear that efforts at "revision" may provide intellectual cover for backsliding of humanitarian and liberty protections. (6) And opponents of even applying the law of armed conflict at all argue that contemporary terrorism threats are insufficiently analogous to military threats to merit its application. (7)
Where this debate, about whether and how the law of armed conflict might warrant adaptation, has fallen short is in its insufficient integration of analytical developments within the counter-terrorism community. This includes both intelligence assessment and relevant specialized social sciences. (8) Legal debate has tended to rely on a snapshot view of terrorism, or to speak in terms of "terrorist threats" as a monolithic category. This debate often fails to consider diverse sub-categories of actors and how terrorism or other non-state threats of tomorrow may look very different from those of yesterday and today. United States government rhetoric may be partly to blame for the conceptual haziness inherent in references to "terrorist groups," "terrorism," or even just "terror" as an undifferentiated policy construct.
This article considers a major debate in the American and European counterterrorism analytic community--whether the primary terrorist threat to the West is posed by hierarchical, centralized terrorist organizations operating from geographic safe havens, or by radicalized individuals conducting a loosely organized, ideologically common but operationally independent fight against western societies--and this debate's implications for the law of armed conflict.
While the broad consensus is that both phenomena are of great concern and not neatly separable, each view of the main terrorism threat to Western developed states poses a different set of challenges to current law of war models. If the main terrorist threat to the United States and its European allies reflects the former, "top-down" model, then existing law of war principles are a useful starting point, and with modest reform may be adapted to combating international terrorist organizations. (9) If the main terrorist threat resembles the latter, "bottom-up" model, existing law of war principles have much less to offer, and according to many proponents of that model their application is likely to be strategically counterproductive. …