At Just Security, my friend Ryan Goodman has posted a long analysis of Serdar Mohammed v. Ministry of Defense, in which the UK High Court held that IHL neither authorizes nor regulates detention in non-international armed conflict (NIAC). That decision will soon be considered by the Court of Appeal.
In his post, which is a must-read, Ryan states that he agrees with the High Court that IHL does not authorize detention in NIAC but disagrees that IHL does not regulate such detention. I share Ryan’s position on the first point, but I disagree with him — and agree with Justice Leggatt in Serdar Mohammed — on the second. In a subsequent post, I will address Ryan’s argument that “whatever is permitted in international armed conflict is permitted in noninternational armed conflict.” I have described that argument in a forthcoming book chapter as “reasoning by analogy”; Ryan rejects that description and says he is engaging in “reasoning by structure.” I will try to show in the next post that the “whatever is permitted” argument is problematic no matter how we describe its underlying reasoning.
In this post, I want to focus Ryan’s argument that, contrary to Justice Leggatt, IHL does in fact regulate the permissible grounds for detention in NIAC. Here is what he says (emphasis mine):
So far we have discussed the permissive boundaries of detention in NIAC but what about limitations on states in these contexts? IHL also imposes a set of prohibitions on the grounds for detention in internal armed conflict. That is, multiple sources conclude that IHL prohibits arbitrary deprivation of liberty in NIAC (see footnote 12 of the AJIL article, for example). Subsequent to that law review article, several important states through the Copenhagen Process—including “specially affected” states which is a significant category for customary international law purposes—explicitly accepted such restrictions on detention in NIAC. Consider also the ICRC’s statement in a Background Paper on detention for the regional consultations 2012-2013: “In terms of grounds for internment, the ICRC, along with a growing international consensus of experts considers that ‘imperative reasons of security’ is an appropriate standard for internment in NIAC.” And a Report by a group of experts convened by the ICRC and Chatham House “quite easily” reached a consensus that in NIACs “parties to a conflict may capture persons deemed to pose a serious security threat and that such persons may be interned as long as they continue to pose a threat.” (See also the ICRC’s customary international humanitarian law Rule 99: Deprivation of Liberty).
To begin, it’s worth noting that Ryan does not seem to be “reasoning by structure” here — he seems to be arguing that, as a matter of customary international law, IHL prohibits arbitrary detention in NIAC. After all, he specifically mentions custom and “specially affected” states in the context of the Copenhagen Process. Moreover, he refers to the ICTY’s jurisdiction decision in Tadic both here and in his superb law-review article on security detention — and Tadic specifically based its (methodologically dubious) extension of IAC-based rules of IHL to NIAC on customary international law. As it said with regard to those rules (para. 127), “it cannot be denied that customary rules have developed to govern internal strife.”
If Ryan is claiming that IHL prohibits arbitrary detention in NIAC as a matter of customary international law, I have no theoretical objection to his argument. Indeed, as I’ll explain in my next post, my position is that international human rights law (IHRL) governs the regulation of detention in NIAC precisely because there are no contrary customary rules of IHL that can serve as the lex specialis of detention. If there are such customary rules, IHL may well displace IHRL (depending on how we understand the lex specialis principle).
That said, I take issue with Ryan’s claim that (as a matter of custom?) IHL prohibits arbitrary detention in NIAC — a standard that has no basis in the conventional IHL of NIAC and is normally associated with IHRL…