Following up on Ashley’s piece on Brian Egan’s good speech at the ASIL meeting last week, I have a piece at Time explaining that that Egan adopts the Bush administration’s controversial preemption doctrine in all but name. The basic idea of preemption is that the “imminence” component of legitimate anticipatory defense under international law must be expanded and made more flexible due to the fact that terrorists and rogue states can hide powerful weapons of mass destruction that do significant harm with little notice.
The doctrine most famously articulated in Bush’s National Security Strategy of 2003:
For centuries, international law recognized that nations need not suffer an attack before they can lawfully take action to defend themselves against forces that present an imminent danger of attack. Legal scholars and international jurists often conditioned the legitimacy of preemption on the existence of an imminent threat—most often a visible mobilization of armies, navies, and air forces preparing to attack.
We must adapt the concept of imminent threat to the capabilities and objectives of today’s adversaries. Rogue states and terrorists do not seek to attack us using conventional means. They know such attacks would fail. Instead, they rely on acts of terror and, potentially, the use of weapons of mass destruction—weapons that can be easily concealed, delivered covertly, and used without warning. …
The greater the threat, the greater is the risk of inaction—and the more compelling the case for taking anticipatory action to defend ourselves, even if uncertainty remains as to the time and place of the enemy’s attack. To forestall or prevent such hostile acts by our adversaries, the United States will, if necessary, act preemptively.
Legal Advisor Will Taft defended the doctrine at the ASIL meeting in 2004:
The concept of imminence in the traditional framework of self-defense must be revisited in the era of weapons of mass destruction (WMDs). Previously, an imminent threat could be most easily imagined as an advancing army or ships on the horizon. Now, in addressing this concept, we must recognize the threat posed by weapons of mass destruction, the intentions of those who possess such weapons, and the catastrophic consequences of their use. In the era of WMDs, the right to self-defense could be meaningless if a state cannot prevent an aggressive first strike. A first strike could completely destroy the defending state's ability to respond to the attack and there is likely to be very little warning before an attack. Moreover, an attack involving WMDs could result in a disaster of catastrophic proportions.
The doctrine of preemption to prevent a catastrophe resulting from an attack by weapons of mass destruction is, however, a natural extension of-and fully consistent with-the traditional right of individual and collective self-defense to ensure that the right of self defense attaches early enough to be meaningful and effective.
[S]ince the United States cannot remain idle in the face of potentially catastrophic harm to its people, the threat of weapons of mass destruction, the intentions of those who possess such weapons, and the grave consequences of their use must be weighed in judging the "imminence" of a threat.
Deputy AAG John Yoo provided a more extended the legal defense of preemption in the AJIL:
Although the dictionary definition of "imminent" focuses on the temporal, under international law the concept of imminence must encompass an analysis that goes beyond the temporal proximity of a threat to include the probability that the threat will occur.
In addition to the probability of the threat, the threatened magnitude of harm must be relevant. The advent of nuclear and other sophisticated weapons has dramatically increased the degree of potential harm, and the importance of the temporal factor has diminished. Weapons of mass destruction threaten devastating and indiscriminate long-term damage to large segments of the civilian population and environment. In addition, the danger posed by WMD is exacerbated by the possibility that the means of delivery may be relatively unsophisticated— for example, a "dirty bomb" driven into a building by a suicide bomber, or the spread of a biological agent with an ordinary crop duster. At the same time, the development of advanced missile technology has vastly improved the capability for stealth, rendering threats more imminent because there is less time to prevent their launch. …
At least in the realm of WMD, rogue nations, and international terrorism, however, the test for determining whether a threat is sufficiently "imminent" to render the use of force necessary at a particular point has become more nuanced than Secretary Webster's nineteenth-century formulation. Factors to be considered should now include the probability of an attack; the likelihood that this probability will increase, and therefore the need to take advantage of a limited window of opportunity; whether diplomatic alternatives are practical; and the magnitude of the harm that could result from the threat. If a state instead were obligated to wait until the threat were truly imminent in the temporal sense envisioned by Secretary Webster, there is a substantial danger of missing a limited window of opportunity to prevent widespread harm to civilians. Finally, in an age of technologically advanced delivery systems and WMD, international law cannot require that we ignore the potential harm represented by the threat.
Here is Egan’s similar account of the flexible jus ad bellum test when the United States is responding in self-defense "to imminent [threats] before they occur":
When considering whether an armed attack is imminent under the jus ad bellum for purposes of the initial use of force against a particular non-State actor, the United States analyzes a variety of factors, including those identified by Sir Daniel Bethlehem in the enumeration he set forth in the American Journal of International Law—the ASIL’s own in-house publication—in 2012. These factors include the nature and immediacy of the threat; the probability of an attack; whether the anticipated attack is part of a concerted pattern of continuing armed activity; the likely scale of the attack and the injury, loss, or damage likely to result therefrom in the absence of mitigating action; and the likelihood that there will be other opportunities to undertake effective action in self-defense that may be expected to cause less serious collateral injury, loss, or damage. The absence of specific evidence of where an attack will take place or of the precise nature of an attack does not preclude a conclusion that an armed attack is imminent for purposes of the exercise of the right of self-defense, provided that there is a reasonable and objective basis for concluding that an armed attack is imminent.
My conclusion in Time:
Egan here embraces all of the tenets of Bush preemption. Though he discusses the principle in the context of force against non-state actor terrorists, the rationale applies readily (and indeed less controversially) to states themselves. If anything, Egan announces a broader principle than Bush’s, since he (unlike the Bush team) applies it in the context of threats short of the weapons of mass destruction that motivated Bush.
The Bush team, of course, fatefully applied its preemption theory in the controversial context of Iraq where it turned out that the premises of analysis were false and the consequences of error were enormous. The Obama team, by contrast, is applying its similar theory in a less controversial “light-footprint” context where the terrorists are indeed menacing and the consequences of error much lower. That context makes the principle easier to swallow and will give it broader acceptance and legitimacy. So, too, will the fact that it is articulated by an administration known to be friendly to international law.
Though the contexts for the Obama and Bush preemption principles differ, the principle is the same. But it is the Obama team’s articulation of the principle that will be influential. Future presidents who want to use force in other nations won’t invoke the doctrine used in the disastrous Iraq war. They will instead adopt the functionally identical principle that the Obama administration normalized and legitimated.