The International Rule of Law

The “rule of law” is a concept capacious enough to mean different things to different people. As a result, surface consensus on the value of the rule of law often masks substantial disagreement about critical details. Scholars debate the question of whether the rule of law should be understood in purely formal terms or in substantive terms,Footnote ³ whether it should be viewed as a “thick” or “thin” concept, and whether it is best understood as an end unto itself or merely as a means toward some other end, such as democracy or the realization of human rights.Footnote ⁴ In 2004, UN Secretary-General Kofi Annan described the rule of law on the domestic level as:

This conception of the rule of law translates only imperfectly onto the international domain. In the most basic sense, the notion of international rule of law implies that states (and other international actors, such as the United Nations itself) should be bound by international law. Beyond this, international rule of law also implies a range of principles and requirements to ensure that the laws are in fact binding and that there is a sense of institutional and procedural fairness. Precisely what this requires is the subject of much debate. At the national level, it is generally taken for granted that a robust rule-of-law society must have a strong, independent judiciary. To state the obvious, this does not (yet) exist at the international level, despite the proliferation of international and regional adjudicative bodies of varying sorts.

However, the lack of such an international judicial system does not inevitably render state behavior arbitrary and unpredictable. As Louis Henkin famously reminded us, “almost all nations observe almost all principles of international law and almost all of their obligations almost all of the time.”Footnote ⁶ This suggests that the lack of a strong, independent global judicial system is not necessarily fatal to the realization of the rule of law, insofar as state compliance can often be obtained through other means. These include internal and external reputational pressures, diplomacy, arbitration, concerns about reciprocity and retaliation, ad hoc tribunals, and a range of other dispute-resolution and compliance mechanisms.

Another difficulty relates to how best to translate the concept of “equality before the law” onto the international level. In a strictly formal sense, equality before the law seems to require equality between sovereign states. This, indeed, is how the UN General Assembly appears to interpret the concept of international rule of law. In a September 2012 resolution (adopted without a vote), the General Assembly declared:

This sits somewhat uneasily with the Secretary-General's insistence that the rule of law requires consistency “with international human rights norms and standards.”Footnote ⁸ If we ground our conception of the rule of law in human rights, it is not clear that there is anything normatively compelling about the equality of sovereign states; after all, some states are democratic, while others are repressive; some are wealthy and strong, while others are poor and weak; some have tiny populations, while others are vast.Footnote ⁹ Why should states, which are artificial constructs marked by glaring and often arbitrary differences, be treated equally? But most international law is itself premised on sovereign equality; so for the time being, it is difficult to see how to foster or sustain the international rule of law while jettisoning the principle of sovereign equality.

Of course, as many have pointed out, the UN Charter itself is in this sense difficult to square with rule of law principles. In its creation of the Security Council, the Charter permanently privileges some states over others for reasons that, with the passage of time, seem increasingly arbitrary.Footnote ¹⁰ If states are formal equals, why, some seven decades after the end of the Second World War, should China, France, Russia, the United Kingdom, and the United States be the only states with veto power over Security Council resolutions?Footnote ¹¹

A final problem relates to the lack of mechanisms for ensuring access to law by individuals. The international system is a creation of states, but as human rights norms have been universalized, states have accepted a range of international legal obligations toward individual human beings. At the moment, however, there are still few means for individuals to vindicate their rights within the international system if they cannot get satisfaction through their own state.

It is not the purpose of this essay to examine competing conceptions of the international rule of law or to exhaustively detail the existing rule-of-law problems inherent in the current international system.Footnote ¹² For present purposes, it is probably sufficient to say that whatever else it may entail, the international rule of law requires, at a bare minimum, the “avoidance of arbitrariness” and “procedural and legal transparency.” Put differently, it requires that international law be, in Simon Chesterman's words, “prospective, accessible, and clear.”Footnote ¹³ This is essential for ensuring basic stability: states—and individuals, who act on behalf of states and are acted upon by states—must be able to understand what is expected of them by international law. If it is to have any value at all, international law must provide a reasonably clear basis for predicting state behavior and for holding states to account when their actions do not conform to legal requirements.

This is a fairly formalistic and thin conception of the international rule of law. Nevertheless, even this weak version is undermined when key international law concepts lose any fixed meaning. When an exceptionally powerful state begins to interpret international law in a substantially different way than most other states, it becomes increasingly difficult to predict that state's behavior. And unpredictability can spread: one powerful outlier can pave the way for others, and as more states join the outlier, the foundations of the rule of law begin to crumble.Footnote ¹⁴

A state need not clearly “break” the law for the international rule of law to be challenged or (potentially) undermined. As noted above, occasional incidents of straightforward and blatant rule-breaking may be less threatening than more subtle but continuous challenges to the nature and meaning of international law.Footnote ¹⁵ This is because blatant rule-breaking is both relatively rare and relatively easy to identify; it is also relatively easy to remedy through traditional dispute resolution mechanisms. To some extent, occasional blatant rule-breaking can even shore up the international rule of law, by inspiring other states to reaffirm their shared understanding of law's meaning and by enabling the system to demonstrate its corrective capacities. By so doing, states reinforce the legitimacy, strength, and even-handedness of the law and legal institutions.

Consider an analogy to the domestic context. The rule of law does not require that there be no rule-breakers; it merely requires that rule-breaking be relatively rare and that most instances of rule-breaking be identified and punished. A robust rule-of-law society has laws prohibiting homicide, for instance. If homicides sometimes occur, this does not in itself threaten the rule of law, as long as such homicides are not excessively widespread, are investigated in an evenhanded fashion, and efforts to investigate and punish them are generally successful. But if the concept of “homicide” loses all clarity—if a significant number of states or courts redefine it by, for instance, adopting extremely permissive and expansive definitions of self-defense—laws against homicide may cease to operate predictably.Footnote ¹⁶

When it comes to the rule of law, the introduction of excessive and ongoing uncertainty is thus far more threatening than occasional blatant rule-breaking. Some vagueness and ambiguity is inevitable and even desirable in an international society that lacks a judicial system, but the introduction of excessive uncertainty wholly undermines the possibility of clarity, stability, predictability, and nonarbitrariness.

U.S. Drone Strikes: Known Unknowns

U.S. drone strikes have grown increasingly controversial in the last few years. This is not because there is anything inherently sinister about drones as such; armed drones merely represent the latest in a long line of technological developments designed to enable the delivery of force from a distance. (In their time, the crossbow and the cannon were also condemned as devilish and dishonorable inventions).Footnote ¹⁷ For political decision-makers, unmanned aerial vehicles have obvious advantages: they are cheaper to produce than manned aircraft with comparable payloads; their use creates no short-term risk to American lives; and, relative to other weapons-delivery systems, their enhanced surveillance capabilities reduce the likelihood of killing anyone other than the intended target.

As it happens, drone technologies improved dramatically just as the United States, struggling to respond to the threat of transnational terrorism after 9/11, began to perceive an increased need for low-cost, low-risk cross-border uses of force. Terrorist threats can come from anywhere, but it is impractical to use conventional military force everywhere. (The wars in Afghanistan and Iraq were a powerful reminder of this fact.) In certain situations, drone strikes appear to offer a cheaper, easier, and safer means of fighting terrorists.

The first U.S. drone strike is believed to have occurred in 2002, when a Hellfire missile launched by a Predator drone killed four suspected al-Qaeda members in Yemen.Footnote ¹⁸ Drone strikes remained a rarity until 2008, however, when the Bush administration launched thirty-six strikes in Pakistan.Footnote ¹⁹ Beginning in 2008, the United States began to make more frequent use of strikes from unmanned aerial vehicles. Most controversially, the United States has greatly increased its reliance on drone strikes outside of traditional, territorially-bounded battlegrounds.Footnote ²⁰ In Pakistan, the number of suspected strikes rose from four in 2007 to a peak of 122 in 2010, before declining to forty-eight strikes in 2012.Footnote ²¹ In Yemen, suspected drone strikes rose from three or four in 2010 to an unknown peak in 2012. (There appears to have been at least twenty-six strikes in Yemen in 2012, and possibly as many as eighty-seven.Footnote ²²) The United States has also carried out a smaller number of strikes in Somalia, and there are unconfirmed rumors of U.S. drone strikes in MaliFootnote ²³ and the Philippines as well. All told, U.S. drone strikes have killed an estimated 4,000 people in Pakistan, Yemen, and Somalia.Footnote ²⁴ The percentage of civilian deaths is unknown, and existing estimates are controversial.

Almost everything about U.S. drone strikes is shrouded in secrecy. For the most part, the U.S. government does not comment on or acknowledge reported drone strikes that take place outside of “hot” battlefields, and it does not release lists of those targeted or killed. Senior Obama administration officials have offered oblique accounts of the drone strike program, but these have been at an extremely high level of generality, with few factual details or details relating to the administration's legal analysis. Even President Obama's speech on drones, delivered at the National Defense University on May 23, 2013, did not serve to shed much light on the subject.Footnote ²⁵ As a result, it is impossible to describe current U.S. practices or internal procedures with any certainty, and also impossible to know exactly what legal constraints U.S. officials believe to exist, and whether and how these have changed in the last few years. We do know, however, that as a matter of international law the United States believes itself to be in an armed conflict with “al-Qaeda and its associated forces.”Footnote ²⁶ We know the United States therefore considers “al-Qaeda operatives” to be targetable as “combatants,” but we do not know precisely how it identifies or defines al-Qaeda operatives, agents, or members, or how it defines the term “combatants” and applies it in the murky context of transnational terrorism. We also do not know precisely how the United States understands the term “civilian” in the context of terrorism, or the concept of “direct participation in hostilities.” Finally, we do not know how the United States defines or identifies “associates” or “co-belligerents” of al-Qaeda.

For example, President Obama's speech on drone warfare—which one might think would contain the most cogent explanation of America's position on the law of drone warfare—only offered the following nugget in support of its legality:

Understanding U.S. legal arguments is made more difficult by the fact that administration spokespersons often appear to oscillate between putting forward a law of armed conflict framework and a self-defense framework when justifying drone strikes. At times, U.S. officials appear to have suggested that the self-defense framework supplements the armed conflict framework.Footnote ²⁸ In recent months, however, their language has suggested that the United States has shifted entirely from an armed conflict framework to a self-defense framework.Footnote ²⁹ In any case, a self-defense framework possesses as many unknowns as an armed conflict framework: we do not entirely know how the United States understands the terms “armed attack” or “imminent” (though leaked memos offer some disturbing hints), nor do we know how the United States evaluates issues of necessity and proportionality.

With regard to sovereignty issues, U.S. officials have repeatedly stated that they only use force inside the borders of a sovereign state when that state either consents to the use of force or is “unwilling and unable” to take appropriate action to address the threat itself. We do not know, however, how the United States evaluates issues of consent in situations in which consent is ambiguous (such as in the case of Pakistan, in which the executive branch reportedly gave tacit consent to drone strikes but publicly denied it, and in which the legislative and judicial branches have denied consent). We also do not know precisely what criteria the United States uses to determine whether a state is “unwilling or unable” to take appropriate action.

U.S. Drone Strikes and the International Rule of Law: Core Concepts Lose Their Meaning

That is a lot of unknowns. Nevertheless, if we piece together public statements by U.S. officials, leaked government documents, and the existing evidence about past strikes and their targets, the basic outlines of the United States' legal theory underlying targeted killings become visible. While much remains uncertain, it is clear that recent statements and practices by the United States represent a substantial challenge to international legal rules on the use of armed force with regard to both jus ad bellum and jus in bello rules.

Let us start with jus ad bellum rules, the rules concerning when force may be initiated. Under the UN Charter, states agree to “settle their international disputes in a peaceful manner” and “refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state.” This is generally viewed as a blanket prohibition on the use of force by one state inside the borders of another sovereign state. Chapter VII of the UN Charter outlines just two exceptions to this prohibition. First, if the Security Council identifies “any threat to the peace, breach of the peace, or act of aggression,” it may “take such action by air, sea, or land forces as may be necessary to maintain or restore international peace and security.”Footnote ³⁰ For practical purposes, this means that the Security Council can pass a resolution authorizing one or more member states to use force to carry out its mandates. The second exception relates to self-defense. In Article 51 the Charter says, “Nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a Member of the United Nations, until the Security Council has taken the measures necessary to maintain international peace and security.”

It is difficult to evaluate U.S. drone strikes under these rules. Clearly, the Security Council has not expressly authorized the use of force by the United States in Pakistan, Yemen, or Somalia. The Council has, however, expressly recognized that terrorist attacks can trigger a right to use force in self-defense, and the Council implicitly gave its approval to the November 2001 U.S. military intervention in Afghanistan. In Security Council Resolution 1368, passed one day after the terrorist attacks of 9/11, the Council stated that “such acts, like any act of international terrorism,” constitute “a threat to international peace and security.”Footnote ³¹ In the same resolution, the Council also reaffirmed “the inherent right of individual or collective self-defence in accordance with the Charter.”Footnote ³²

This resolution and those that followedFootnote ³³ were viewed by the United States (and by the international community generally) as sufficient to permit the lawful use of force in Afghanistan by the United States and NATO. Most commentators agreed that the initial U.S./NATO campaign constituted a clear case of individual and collective self-defense after the 9/11 attacks.Footnote ³⁴ On December 20, 2001, the Security Council authorized the creation of the International Security Assistance Force for Afghanistan (ISAF),Footnote ³⁵ thus bringing the war in Afghanistan under the formal umbrella of Security Council–authorized uses of force. In fact, from a rule-of-law perspective, the process leading to military action in Afghanistan was exemplary: the Security Council noted that an armed attack had occurred and that states had the right to use force in self-defense. The United States and NATO states then took action on their own “until the Security Council [took the] measures necessary to maintain international peace and security” by authorizing an international force.Footnote ³⁶

Subsequent uses of force by the United States for counterterrorism purposes outside Afghanistan pose a more complicated question. Security Council Resolution 1373 acknowledges that any act of international terrorism gives rise to a right to self-defense and calls upon UN member states to “work together to prevent and suppress terrorist acts” and “take the necessary steps to prevent the commission of terrorist acts.”Footnote ³⁷ The United States appears to regard such generic statements as sufficient international legal basis for discrete, ongoing uses of force against suspected terrorists around the globe.Footnote ³⁸ This view is not wholly implausible: if all terrorist acts threaten international peace and security and give rise to a right to self-defense, and if the Security Council has tasked states with taking “necessary steps” to prevent future terrorist acts, this seems like a reasonable basis for concluding, at a minimum, that there is nothing manifestly unlawful about U.S. drone strikes against terrorists (assuming drone strikes can plausibly be viewed as “necessary”).

From a broader rule-of-law perspective, however, this interpretation presents several difficulties. For one thing, it seems to be an open-ended invitation for states to engage in the unilateral use of force against suspected terrorists. But if it is open-ended, it renders meaningless the UN Charter's proviso that the right to use force in self-defense lasts “until the Security Council has taken [the] measures necessary to maintain international peace and security.”Footnote ³⁹ This is an important implied limitation on the right to use force: the Charter language clearly anticipates that the unilateral use of force in self-defense will be temporary in nature, undertaken as an emergency measure only. Once the emergency is over, the Charter appears to assume either that peace will have been restored or that the state under attack will have dispelled the imminent threat and be in a position to request that the Council take any measures needed to ensure its longer-term safety.

Regardless of whether the Council takes action to address a threat, a state's right to respond to an armed attack is clearly subject to some temporal limitations; it does not last indefinitely.Footnote ⁴⁰ Thus, more than seventy years after the Pearl Harbor attacks, the United States no longer has a legal basis for using force in self-defense against Japan; similarly, from an international law perspective, it is doubtful that the 9/11 attacks alone give rise to an indefinitely continuing right to use force in self-defense. This view is consistent with the traditional understanding of the right to self-defense in international law, which limits the unilateral use of force to situations in which a state is responding to a recent “armed attack” or to an “imminent” threat of future attack. And at least on a superficial level, the United States appears to accept this view: “We act against terrorists who pose a continuing and imminent threat to the American people,” President Obama asserted in a May 2013 speech.

This does not help us determine the legality of U.S. drone strikes, however, because it merely shifts the question to how we define “imminent threat.” And here, what we know of U.S. reasoning is not reassuring. Traditionally, there has been substantial consensus among states and international law experts that an imminent threat is one that is concrete and immediate, rather than speculative or remote.Footnote ⁴¹ But according to a leaked 2011 Justice Department White Paper—the most detailed legal justification that is publicly available—the United States is now taking a radically different approach to defining imminence.Footnote ⁴² According to the White Paper, the requirement that force only be used to prevent an “imminent” threat “does not require the United States to have clear evidence that a specific attack on U.S. persons and interests will take place in the immediate future.”Footnote ⁴³ This seems—and is—at odds with the traditional view. The White Paper goes on to assert that “certain members of al-Qa'ida are continually plotting attacks . . . [and] would engage in such attacks regularly [if they] were able to do so, [and] the U.S. government may not be aware of all al-Qa'ida plots as they are developing and thus cannot be confident that none is about to occur.”Footnote ⁴⁴ As a result, the White Paper concludes that any person deemed to be an operational leader of al-Qaeda or its “associated forces” inherently presents an imminent threat at all times—and as a result, the United States can lawfully target such persons at all times, even in the absence of specific knowledge relating to planned future attacks.

At risk of belaboring the obvious, this understanding of imminence turns the traditional international law interpretation of the concept on its head. Instead of reading the imminence requirement to mean that states must have concrete knowledge (or at least reasonable suspicion) of an actual impending attack in the near future, the United States appears to construe lack of knowledge of a future attack as the justification for using force; that is, since the United States “may not be aware of all Al Qa'ida plots . . . and thus cannot be confident that none is about to occur,”Footnote ⁴⁵ force is presumed always to be justified against the kinds of people considered likely to “engage in . . . attacks . . . if [they] were able to do so.”Footnote ⁴⁶ From a rule-of-law perspective, this is a radical assault on a once-stable concept. If “imminent threat” can mean “lack of evidence of the absence of imminent threat,” it is impossible to know, with any clarity, the circumstances under which the United States will in fact decide that the use of military force is lawful.

The rule-of-law conundrums do not end there. Under international law (customary as well as treaty-based), the use of force in self-defense must also be consistent with the principles of necessity and proportionality.Footnote ⁴⁷ The principle of necessity tracks the “just war” requirement that force should be used only as a last resort, and when measures short of force have proved ineffective; the principle of proportionality relates to the amount and nature of the force used. Given the lack of transparency around U.S. drone strikes, it is impossible to say whether any given strike (or the totality of strikes) satisfies these legal and ethical principles.

Are all drone strikes “necessary”? Could nonlethal means of combating terrorism—such as efforts to disrupt terrorist financing and communications—be sufficient to prevent future attacks? Might particular terror suspects be captured rather than killed? Do drone strikes inspire more terrorists than they kill?Footnote ⁴⁸ Also, to what degree does U.S. drone policy distinguish between terrorist threats of varying gravity? If drone strikes against a dozen targets prevented another attack on the scale of 9/11, few would dispute their appropriateness or legality—but we might judge differently a drone strike against someone unlikely to cause serious harm to the United States. Unfortunately, if U.S. decision-makers generally lack specific knowledge about the nature and timing of future attacks—which the White Paper acknowledges—judgments of necessity and proportionality literally become impossible. How can one decide if lethal force is necessary to prevent a possible future attack about which one knows nothing? How can proportionality be determined? Here again, the U.S. legal theory underlying targeted killing makes it impossible to apply key principles in a meaningful way. Both necessity and proportionality come to be evaluated in the context of purely hypothetical worst-case scenarios (in theory, any terror suspect might be about to unleash another catastrophic attack on the scale of 9/11). As a result, these “limitations” on the use of force establish no limits at all.

The problem goes still deeper. On an ontological level, it is extraordinarily difficult to know how to categorize U.S. drone strikes and other targeted killings. Should they be construed as a series of discrete uses of force, each of which must be independently evaluated for adherence to self-defense principles? Or do they constitute, in effect, an ongoing use of force made up of many individual strikes, which should be evaluated collectively?Footnote ⁴⁹ If the latter, can the United States be said to be in an “armed conflict” with militants in Pakistan, suspected al-Qaeda associates in Yemen, members of the al-Shabaab organization in Somalia, and assorted other unknown groups and individuals? The Obama administration, like the Bush administration before it, asserts that the answer is yes. Their position is that an armed conflict can exist between a state and one or more nonstate entities, even if those nonstate entities are not publicly identified, their membership criteria cannot be clearly defined, they lack any hierarchical structure, and their activities are geographically dispersed.

Outside the United States, most others disagree. In Europe, for instance, as a recent European Council on Foreign Relations report by Anthony Dworkin notes, most legal scholars and courts “[reject] the notion of a de-territorialised global armed conflict between the U.S. and al-Qaeda,” and believe that a “confrontation between a state and a non-state group only rises to the level of an armed conflict if the non-state group meets a threshold for organization . . . there are intense hostilities between the two parties . . . [and] fighting [is] concentrated within a specific zone (or zones) of hostilities.”Footnote ⁵⁰

This shifts us from jus ad bellum questions to jus in bello questions. From a rule-of-law perspective, it is crucial that we be able to determine the existence (or nonexistence) of an armed conflict: if the United States is in an armed conflict, many of the rules relating to the use of force change. In an armed conflict, it is acceptable to target enemy combatants based simply on their status as enemy soldiers. If there is no armed conflict, such status-based targeting ceases to be acceptable, and we are thus back to the requirement that force may only be used to ward off an imminent threat (which, of course, the United States appears to conflate with status).

The international rule of law dilemmas here should be obvious. While the scope of international law rules relating to self-defense and armed conflict have always been somewhat controversial, the irregular but continuing nature of U.S. drone strikes adds additional layers of complexity. In a domestic context, such ontological disputes would not pose an ongoing challenge to the rule of law: although significant legal vagueness and ambiguity might persist for a time, the judiciary would eventually resolve the uncertainty, by selecting one interpretation over the others, or new legislation would be passed to resolve the uncertainties.Footnote ⁵¹ In the international context, however, there is no referee able to make such vital calls. There is no judicial system and no “legislature.” States can enter into multilateral treaties, but there is no set procedure for creating such treaties, and in practice treaties frequently take decades to be negotiated and further decades to enter into force. Furthermore, the structure of the Security Council makes it near impossible to imagine a Council-imposed resolution to any of these questions. Russia and China (and perhaps other Council members as well) would likely block any U.S. effort to gain Council authorization for drone strikes or create some international force empowered to engage in such strikes. At the same time, the seemingly open-ended language of the Council's post-9/11 resolutions cannot be rolled back, since the United States would use its veto to block any such efforts. For the same reason, U.S. actions cannot be criticized by the Council.

At the moment, the United States itself—as the globe's only military superpower—is the sole arbiter of its own actions: with zero transparency, it determines which laws to apply and it comes up with its own interpretation of core concepts. Or, to put it in more familiar terms, the United States is judge, jury, and executioner all rolled into one. It decides how to interpret the law to which it is subject; it decides what can be counted as evidence and how to evaluate that evidence; and, ultimately, it kills.

It is worth noting one last concept that has been increasingly destabilized by post-9/11 U.S. legal theories. This is the concept of sovereignty itself, long a core building block of the Westphalian international legal order. Admittedly, the absoluteness of sovereignty has always been a legal fiction, and in recent decades globalization has reduced the salience of state borders even as the emergence of human rights law has chipped away at the state's normative standing. Nevertheless, the concept of sovereignty—however frayed and problematic—remains a bulwark against unpredictable international conflict. Recent U.S. pronouncements suggest, however, that this will not remain true for much longer. U.S. officials have repeatedly stated that the United States will only use force on the territory of other sovereign states if that state either consents or is “unwilling or unable to suppress the threat posed by the individual being targeted.” While this sounds superficially reasonable, the logic is in fact circular, since the United States is the self-appointed arbiter of whether a state is “unwilling or unable.”

Thus, if the United States—using its own malleable definition of “imminent”—decides that an individual in, say, Pakistan poses a threat to the United States and requires killing, sovereignty is a nonissue. Either Pakistan will consent to a U.S. strike inside its territory or it will not consent. And if Pakistan does not consent—on the grounds, perhaps, that it does not agree with the U.S. threat assessment—then Pakistan is, ipso facto, “unwilling or unable to suppress the threat posed by the individual being targeted.”Footnote ⁵²

This is a legal theory that more or less eviscerates traditional notions of sovereignty, and has the potential to significantly destabilize the already shaky collective security regime created by the UN Charter.Footnote ⁵³ After all, if the United States is the sole judge of whether and when it can use force inside the borders of another state, any other state strong enough to get away with it is likely to claim similar prerogatives.