Armed Conflict Cybersecurity & Tech Terrorism & Extremism

On the Legality of the Strike That Killed Ayman Al-Zawahiri

Robert Chesney
Wednesday, August 3, 2022, 8:01 AM

In the culmination of a manhunt that lasted almost 21 years, the U.S. government appears to have located and killed Ayman al-Zawahiri. Here are the legal questions the Biden administration likely worked through before the strike.

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Early in the morning on Sunday this past weekend, Ayman al-Zawahiri stepped out onto a balcony of a home in Kabul. It was something he’d done many times before without apparent incident, but this time would be his last. U.S. personnel had identified him, and had a drone in place to take the shot. A manhunt that began immediately after 9/11 and lasted nearly 21 years was over at last.

Context: Zawahiri Then and Now

 As Osama bin Laden’s successor to leadership of al-Qaeda’s core organization, Zawahiri has played an important role in sustaining the network over the decade (if only by virtue of his persistence in staying free and alive, embodying successful defiance of the efforts of the United States and its allies; his actual efficacy in other terms has been questioned). But his larger historical significance revolves around his influence on Osama bin Laden beginning in the 1980s, at the time of the war with the Soviets in Afghanistan. As Larry Wright explains in riveting detail in this 2002 profile, Zawahiri by that time was a seasoned extremist, and a key figure in Egyptian Islamic Jihad. At a pivotal moment in the aftermath of the Soviet withdrawal, Zawahiri’s was the key voice urging bin Laden to focus on developing operations against the “Far Enemy”—that is, the United States—in contrast to Abdullah Azzam, another influential jihadist at the time, who preferred concentrating on closer goals like attacking Israel and Egypt. After Azzam died, Zawahiri became the central influence on bin Laden, and soon the elements of “The Base”—al-Qaeda—were in place. Repeatedly, up through and including the 9/11 attacks, Zawahiri played important roles in encouraging, vetting, and supporting violence against Americans.

Had the United States succeeded in locating and killing Zawahiri in Afghanistan in the early days of the post-9/11 period, things would have been different. Such an event likely would have loomed much, much larger in the American consciousness then, perhaps close to what would occur much later with the eventual killing of Osama bin Laden. Occurring instead two decades later, Zawahiri’s killing has generated a fair amount of news coverage along with a brief prime-time appearance from the president, but the overall footprint of the story seems certain to be limited, relatively speaking. And there’s good reason for that.

First, the threat posed by the central al-Qaeda network has diminished over the past two decades, thanks to the success of U.S.-led counterterrorism efforts, and the splintering of al-Qaeda first into franchises and then into rivalrous networks with the emergence of the Islamic State and its affiliates.

Second, a host of other threats, apart from terrorism, have gradually supplanted the once-dominant “war on terrorism” conception of primary national security threats. Russia is waging a war of aggression in Ukraine. China poses a long-term strategic challenge of the first order, with hints of potential conflict over Taiwan arising uncomfortably often just this week. The United States continues the painful progress from a fierce pandemic into the endemic stage of the coronavirus. Novel technological threats associated with cybersecurity and disinformation abound. Domestic terrorism is now a central concern. Rampant authoritarianism and loss of confidence in the rule of law tear at the bedrock of social and political stability. In the face of all this, and with considerable success in dismantling al-Qaeda over the years, it is no wonder that the war on terrorism began to seem … over, despite any flashy announcement. 

This makes the legal analysis more interesting than it would have been two decades ago, but ultimately the answers turn out much the same. Or at least that is most likely how the administration’s lawyers analyzed things. What follows is a road map to some of the key questions I assume they considered and projections of how they likely analyzed them.

Legality Under U.S. Domestic Law

From a U.S. legal perspective, the core question in a case like this (involving the use of lethal force against a non-U.S. person outside the United States) involves the authority of the Biden administration to conduct the strike. As noted above, after all, many people probably have come to view the whole idea of the war on terrorism as a thing of the past, including especially inside Afghanistan given the formal U.S. withdrawal. But there is zero doubt that this is not the administration’s position. Notwithstanding the changes described above, this administration continues to maintain (like the Bush, Obama, and Trump administrations before it) that the 2001 Authorization for Use of Military Force remains operative, meaning that the only important questions from a separation of powers perspective are whether the AUMF applies to the organization in question and whether the individual involved is relevantly connected to that organization. And here those are exceptionally easy questions to answer, for the AUMF’s organizational scope always has most readily encompassed core al-Qaeda, and arguably no one alive at the time of the strike better embodied core al-Qaeda than Zawahiri. That the 2001 AUMF applied to this strike, in short, is not a hard question.

What of the fact that the United States withdrew its overt military presence from Afghanistan? As I discuss in more detail below, this change raised questions about the continuing relevance of the law of armed conflict as to any activities that the United States might yet conduct there, and for similar reasons it raised questions about the continuing relevance of the AUMF vis-a-vis the Taliban. But nothing about the withdrawal from Afghanistan suggested a U.S. government intent to declare an end to the AUMF’s relevance as to al-Qaeda. Indeed, the government expressly and persistently asserted its continued authority and intent to conduct “over the horizon” strikes on al-Qaeda and possible other targets, when the occasion might arise. And here was such an occasion.

How about the fact that the strike apparently was not carried out by the U.S. military and thus almost certainly was conducted by the CIA as a Title 50 covert action? Nothing new about that; for nearly two decades the CIA has had authority to use lethal force for at least some counterterrorism operations, and whatever the policy merits of that institutional decision there is no serious legal argument that the CIA somehow is precluded from carrying out such strikes. To which one might respond: Ah, but what of Executive Order 12333 and its famous prohibition on assassination? For starters, that prohibition is not specific to the CIA; it applies to all U.S. personnel of whatever agency, and for that matter to others acting at the behest of the United States. But more importantly, the long-standing position of the U.S. government is that it is not an assassination to use lethal force either in the context of armed conflict or otherwise when acting in self-defense in response to a threat to American lives. For more details on that, please see my 2014 article “Postwar.” There, I explain how the United States some seven years ago already had shifted from an armed conflict model to a self-defense model for lethal force outside the combat zone of Afghanistan; now, it’s just that this is true for Afghanistan too.

Legality Under International Law

As has generally been the case throughout the past two decades, the more interesting legal questions raised by drone strikes involve various areas of international law. Let’s consider three of them: the U.N. Charter, the law of armed conflict (aka international humanitarian law), and international human rights law. 

The U.N. Charter framework, in this context, is where we look to understand whether the Zawahiri strike might have violated Afghanistan’s sovereign rights. The charter does, after all, forbid the use of force in international affairs as a default matter, and as the Taliban have already made clear in denouncing the Zawahiri strike the de facto rulers of Afghanistan did not consent to this strike (or at least that is their public position; it’s not beyond the realm of possibility that a faction within the Taliban played a role in alerting the United States to Zawahiri’s presence in Kabul, as he was apparently being sheltered in the home of a senior figure in the Haqqani family). This complicates matters, of course, but the U.S. position in other locations (like Pakistan and Syria) has long been that the protections of Article 2(4) effectively are waived insofar as the government is unable or unwilling to halt armed attacks associated with persons sheltering within their borders (or, put another way, the U.S. position has long been that necessary and proportionate self-defense can be undertaken in those circumstances). There’s little doubt that the “unwilling” condition applies here.

What about the law of armed conflict? If one begins from the premise that the law of armed conflict applies to this strike, then the analysis that follows is not too difficult. The clearest part of the analysis involves proportionality: The precision of the strike plainly complied with the principle of proportionality, showing a remarkable degree of concern for the welfare of bystanders. Application of the principle of distinction is a bit more interesting here. Throughout the post-9/11 period, the U.S. government has taken the position that al-Qaeda members constitute combatants, not just civilians that might directly participate in hostilities from time to time. From that perspective, Zawahiri’s status as a leader atop the al-Qaeda chain of command, combined with his own involvement in orchestrating attacks, would make him targetable at all times. This would have been the analysis, at any rate, had this strike occurred years ago when al-Qaeda was more active and Zawahiri was more clearly engaged in his leadership capacity. And most likely it was the analysis supporting this strike. But it is worth noting that the passage of time and changing factual circumstances associated with Zawahiri’s level of involvement with al-Qaeda might have made this a trickier question than it once was. 

But all of this matters only if the law of armed conflict still governs the U.S.-al-Qaeda relationship. Does it? The question is complicated. The U.S. position has long been that the law of armed conflict framework applies wherever U.S.-al-Qaeda interactions occur, rather than just in particular geographic zones. That view has been hotly contested for two decades. Through most of that time, however, the situation with respect to operations in Afghanistan was common ground: Almost everyone agreed that there was an armed conflict there. And so, until recently, there would have been little doubt that a drone strike in Afghanistan would be analyzed through the law of armed conflict lens. But now the United States has withdrawn its armed forces from Afghanistan, and thus the argument for applying the law of armed conflict to the use of force there now must rest on the same grounds as when the United States periodically does the same in, say, Somalia. That is, the argument rests on the more general claim that the armed conflict with al-Qaeda continues to exist and continues to be global in its scope (albeit subject to U.N. Charter limitations in practical terms, as mentioned above). 

That almost certainly is the Biden administration’s position, and if so it also provides one of two likely answers to the question of how the administration understands this strike’s compatibility with international human rights law: the lex specialis rule. Under this rule, the law of armed conflict’s rules will take precedence in any situation in which both those rules and the more generic right-to-life concepts associated with, say, the International Covenant on Civil and Political Rights (ICCPR) might also apply. Historically, the U.S. government also has taken the position that our international human rights law treaty obligations in any event do not “travel” with our forces operating abroad. If that’s the Biden administration’s view too—frankly, I don’t know where the State Department is on that question these days—then that would of course eliminate ICCPR-based objections involving the right to life.

From War to Postwar

No one thinks the death of Zawahiri is the end of al-Qaeda, let alone that of other AUMF-covered entities like the Islamic State. There is no doubt that the United States in the months and years ahead will continue to carry out lethal strikes, on occasion, against al-Qaeda and Islamic State targets in those places where captures (whether carried out by the United States or by local partners) do not appear feasible. Increasingly, those strikes will raise difficult questions, as the grounds for asserting the ongoing relevance of the law of armed conflict continue to attenuate. As this occurs, the legal questions surrounding those strikes will become ever more complicated.

Robert (Bobby) Chesney is the Dean of the University of Texas School of Law, where he also holds the James A. Baker III Chair in the Rule of Law and World Affairs at UT. He is known internationally for his scholarship relating both to cybersecurity and national security. He is a co-founder of Lawfare, the nation’s leading online source for analysis of national security legal issues, and he co-hosts the popular show The National Security Law Podcast.

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