The UK’s Most Recent Volley on Defensive Force

The legal position that Attorney General Wright presented yesterday is similar to the one that the United States has advanced in recent years. Here’s what I take to be the core elements of the UK claim:

• The use of force is sometimes permissible to defend against an imminent attack. For an attack to be imminent, the threat must actually be operational: “It is absolutely not the position of the UK Government that armed force may be used to prevent a threat from materialising in the first place.”
• The attack’s imminence is part of why defensive force is necessary. But imminence alone does not make it necessary. For defensive force to be necessary, other options for defending against the anticipated attack, including law enforcement options, must be inadequate.
• Defensive force is permitted against an imminent attack, even if the perpetrators are not state agents. Where non-state actors are involved, the relevant inquiry is whether the attack is being planned in another state that is unable or unwilling to prevent it.

I have three initial reactions to Wright’s speech. First, I applaud him for articulating an official UK position on this area of international law. The United States has, of course, pushed hard to advance novel legal positions to justify its counterterrorism operations. But other states have repeatedly responded to the U.S. claims and practice with silence, at least publicly. That dynamic undercuts the law’s (perceived or actual) relevance. International law can’t adequately serve its functions if states stop using it to engage with one another and communicate their expectations—and to do so even, perhaps especially, when they disagree. So, I would encourage other states to follow Wright’s lead and be more forthright about their own legal positions on the contours of the right to use defensive force.

Second, I think the devil is very much in the details here—in the application of the UK’s position to concrete cases. Drawing on Sir Daniel Bethlehem’s piece in the American Journal of International Law [(2012) 106 AJIL 769], Wright list several factors that might be relevant to determining whether an attack is imminent and grounds for the use of defensive force. These factors include:

1. The nature and immediacy of the threat;
2. The probability of an attack;
3. Whether the anticipated attack is part of a concerted pattern of continuing armed activity;
4. The likely scale and damage of the anticipated attack; and
5. The likelihood that there will be other opportunities to take effective, less injurious action to defend against the attack.

It is not clear how these factors relate to one another, or how much weight any particular one carries. Take the third factor—that an anticipated attack is part of a pattern of armed activity. If this factor is treated as uniquely relevant or weighty, then the UK’s position might not be especially novel. Under the so-called “pinprick” or “accumulation of events” theory that many international lawyers already endorse, multiple small-scale attacks can be considered collectively for purposes of the right to respond with defensive force. Thus, an anticipatory operation might easily be characterized as responsive—not as preventing a future attack but as responding to the ones that have already been committed.

But now look at the fourth and fifth factors. In the context of weapons of mass destruction, these factors might justify even very early strikes, like the reported attack by Israel on a partially constructed nuclear reactor in Syria in 2007. If Syria developed nuclear weapons and used them against Israel, Israel would undoubtedly suffer enormous damage (factor 4). And the most effective, least injurious way for Israel to defend against that possibility might have been for it to act early, before Syria actually developed nuclear weapons (factor 5). Standing alone, then, these factors for assessing imminence are potentially expansive. The question is how and to what extent they are limited either by other factors or by the claim that any anticipatory action is impermissible unless the threat is operational. More clarity on that question would be extremely useful to defining the legal constraints on anticipatory actions.

Finally, Wright’s speech might contain a clue about the UK’s position on the application of international human rights law (IHRL) and international humanitarian law (IHL) in this context. As close observers know, the UK government has been somewhat cagey on this question. Here’s what I take to be the relevant text in Wright’s speech:

“Lethal action will always be a last resort, when there is no other option to defend ourselves against an attack and no other means to detain, disrupt or otherwise prevent those plotting acts of terror. When we take such action, we must do so in accordance with international law including international humanitarian law.”

The “last resort” language sounds in IHRL. But notice that Wright specifically referenced IHL and not IHRL. Reading between the lines, I’d say that he is hedging his bets but ultimately suggesting that, when the United Kingdom uses force in self-defense, IHRL either does not apply or is defined by IHL. That view of IHRL would be contentious in at least some cases in which it might be applied. (It’s worth noting that, although Wright says in the above-quoted text that lethal action is permissible only when “there is no other option,” he elsewhere uses slightly looser language—saying that the relevant standard is whether defensive action is “the only feasible means to effectively disrupt [the] attacks.”)