The British Foreign and Commonwealth Office has submitted an official response to questions posed by the House of Commons Foreign Affairs Committee on the legality of humanitarian intervention without Security Council authorization. This exchange arises out of Prime Minister Cameron’s wish, back in August, to join President Obama’s threat to use force in response to the Syrian government’s use of chemical weapons. As part of its ongoing inquiry, the House of Commons Committee has now published an important Annex A (full text) by HMG, which details the government’s official position. Agree with its conclusions or not, HMG provides a sophisticated and formidable analysis. The document will be sure to figure in future debates—across the legal world—on the use of military force to stop mass atrocity.

[For a diversity of views on this topic, check out Just Security series spurred by Harold Koh’s post on the legality of Obama’s threat to strike Syria.]

The position of HMG is straightforward. It has, as the Annex notes, been stated by the government on several occasions:

“[I]f action in the Security Council is blocked, the position of the Government is that it is permitted under international law to take exceptional measures in order to avert a humanitarian catastrophe.”

One of the most important features of this new document is how it reconciles the UK legal position with the Responsibility to Protect (R2P) reflected in the 2005 World Summit Outcome Document. The question posed by the Parliamentary Committee implied that R2P, and the Outcome Document in particular, fortifies the principle that the Security Council has the exclusive authority to use force in response to a humanitarian catastrophe. The response by the Foreign & Commonwealth Office potentially turns that challenge on its head.

According to HMG, R2P and unilateral humanitarian intervention are essentially two sides of the same coin. More specifically, the document sets forth three related propositions:

The Responsibility to Protect and the 2005 World Summit Outcome Document involve political commitments “aimed at making sure that the Security Council does take action”—and that the Security Council “can and should act” (my emphasis)—when necessary to stop an overwhelming humanitarian catastrophe; The Responsibility to Protect as set out in the Outcome Document “does not address the question of unilateral State action in the face of an overwhelming humanitarian catastrophe;” Unilateral humanitarian intervention is a lawful option when the Security Council fails to take action to stop an overwhelming humanitarian catastrophe.

In other words, R2P and the Outcome Document recognize and support the Security Council’s responsibility to intervene to forcibly stop an atrocity, and international law permits states to act when the Council is blocked from exercising that responsibility. On this view, R2P, the World Summit Outcome Document, and unilateral humanitarian intervention complement one another.

Finally, many readers will also be interested to see how HMG describes the legal position of the United State. Here is the full exchange between the parliamentary body and the Foreign & Commonwealth Office:

“[House of Commons Foreign Affairs Committee:] [T]he Committee would like to know … whether, in the FCO’s understanding, the US’s position is the same as that of the UK on the lawfulness of the use of force without an authorising Security Council resolution under the doctrine(s) of R2P/humanitarian intervention. [Foreign & Commonwealth Office:] The US interpretation of the lawfulness of the use of force without a UNSCR is a question for the US Government and, in any case, will always be case-specific. We believe the US to be as committed to the protection of civilians as the UK. The Administration’s 2010 National Security Strategy makes clear that the US supports the concept of R2P and that in cases when prevention fails, ‘the United States will work both multilaterally and bilaterally to mobilize diplomatic, humanitarian, financial, and – in certain instances – military means to prevent and respond to genocide and mass atrocities.’”

The first sentence in that response appears to dodge the issue. Or does it? If the legality of unilateral humanitarian intervention were determined on a “case-specific” basis, surely that would be incompatible with a position that unilateral humanitarian intervention is categorically prohibited.

In addition to the Just Security series mentioned above, check out Oxford Public International Law’s debate map for a broad set of views on this topic.