I will soon have a longer post on the UK High Court judgment in Mohammed v. Ministry of Defense, but here I want to consider a specific argument that implicates the authority of states to detain in armed conflict. That is, I examine an argument put forward by the British government and addressed by the High Court that the legal authority to kill (implicitly) includes the authority to detain. In short, the greater power includes the lesser power.

A quick word about its importance: It is an argument that arguably guided the Supreme Court in Hamdi v. Rumsfeld in interpreting the scope of the AUMF. ICRC expert group reports have invoked it as a general justification for the authority to detain in non-international armed conflicts (here and here). As Just Security’s Jen Daskal notes in her important law review article on targeting and detention outside of hot battlefields, it is an argument that implicates the scope of authorities entailed in self-defense as a justification for combat operations.  In a future post, I will examine how the argument also intersects with Justice Breyer’s “intriguing suggestions” in Hussain v. Obama for future habeas challenges.

For now, let’s turn to the application of the argument in Mohammed. In a post over at EJIL Talk!, Lawrence Hill-Cawthorne & Dapo Akande summarize the logic of the argument well:

“A seemingly compelling argument that can be made against the view that IHL provides no legal basis to detain in NIACs, is that if IHL provides a legal basis to kill fighters in a NIAC it must also provide the lesser power to detain. Also, it may be argued that if IHL did not provide that lesser power, perverse incentives would be created as participants in an armed conflict would be better off killing than detaining.”

I also defended the argument in a 2009 article in the American Journal of International Law (pp. 55-56). But does it apply to all the complainants in Mohammed (and to all detainees in US custody)?

The logic applies only to members of armed forces and civilians who directly participate in hostilities. It does not apply to civilians who indirectly participate in hostilities—such as security threats under articles 5, 27, 41– 43, and 78 of the Civilians Convention. Those individuals are not lawful targets. The notion that the great power includes the lesser power thus does not apply to their situation. So what would be the source of the power to detain them if there is no power to kill them? Another source of authority or logic would need to apply.

Now consider the petitioners in Mohammed. The opinion directly concerned a suspected Taliban commander—hence an individual the state presumably could have lawfully killed (and thus lawfully detained). But what about the PIL claimants who were also part of the litigation? We know very little about them. But, according to the brief on behalf of Public Interest Lawyers, the British Secretary of State “stated in correspondence that Mr Nazim was ‘suspected of financial facilitation for the insurgency’ [and] that Mr Qasim was ‘suspected of financial crimes and narcotic and lethal aid facilitation’, and that Abdullah had been ‘biometrically linked to a PKM machine gun found at the point of detention, which indicated his involvement with the insurgency.’”

Based on those facts, Mr Nazim and Mr Qasim appear to fit the category of indirect participation in hostilities. Detainable under LOAC? Well, maybe, but not under a theory that the power to kill includes the power to detain.