How to Announce ‘Opinio Juris’

Opinio juris meaning the legal concept, not the blog.  The “Fact Sheet” (linked here to Lawfare) that went out with the new executive order on Guantanamo detainees that Deborah notes below has a final section on international law principles.  The points it makes are not related expressly to Guantanamo or detainees there, but about the broader context of laws of war.  So, the administration announces its support for Additional Protocol II, the one covering non-international armed conflict, and which was supported by the Reagan administration and submitted by it to the Senate in 1987 – but which was never actually ratified.  The other statement by the administration is its support for Article 75 of Additional Protocol I.  Here is the text of the fact sheet on this point:

Article 75 of Additional Protocol I, which sets forth fundamental guarantees for persons in the hands of opposing forces in an international armed conflict, is similarly important to the international legal framework. Although the Administration continues to have significant concerns with Additional Protocol I, Article 75 is a provision of the treaty that is consistent with our current policies and practice and is one that the United States has historically supported.

Our adherence to these principles is also an important safeguard against the mistreatment of captured U.S. military personnel. The U.S. Government will therefore choose out of a sense of legal obligation to treat the principles set forth in Article 75 as applicable to any individual it detains in an international armed conflict, and expects all other nations to adhere to these principles as well.

On the substantive side, note that the administration states that it “continues to have significant concerns with Additional Protocol I,” and hence presumably will not be pushing for ratification.  On the procedural side, if I can call it that, the statement says that the administration will choose “out of a sense of legal obligation” to treat the principles of Article 75 as applicable to any individual it detains in an international armed conflict.  The quoted language is, of course, the classic expression of the “intentional” part of “state practice and opinio juris.”  I think it is a good move for the administration to make this clear as a matter of formal and unmistakeable language of international law, and think that US administrations need to have a better process for informing the world – including, at this point, courts everywhere – of the formal opinio juris of the United States.