A recent Presidential Memorandum directs the Secretary of Defense to develop a preliminary plan to defeat ISIS. The plan “shall include . . . recommended changes to any United States rules of engagement and other United States policy restrictions that exceed the requirements of international law.” As Luke Hartig recently explained, these Obama-era policy restrictions—particularly those in the well-known 2013 Presidential Policy Guidance (PPG)—are supported by a range of moral, political, and military considerations. So, too, are various nonpublic military rules of engagement (ROEs). Accordingly, the Secretary of Defense may conclude that more permissive targeting policies, though tactically advantageous, would prove strategically self-defeating, and that therefore most or all of the Obama-era rules ought to be retained.

Earlier this week, Yemeni authorities appeared to withdraw their government’s consent to U.S. ground operations after a number of civilians were killed during a raid by U.S. Special Forces. Yemen’s foreign minister later clarified that his government had not suspended cooperation with the United States, but insisted that “any counterterrorism operations carried out in Yemen should continue to be in consultation with Yemeni authorities and have precautionary measures to prevent civilian casualties.” Going forward, other partners—most notably Iraq—may condition their consent to U.S. military operations on strict targeting policies that protect their civilian population. For obvious reasons, both legal and practical, such considerations ought to inform any “plan” to defeat ISIS.

In this post, however, I wish to suggest that the premise of the Order is mistaken, or at least exaggerated. In my view, U.S. targeting policies, including the PPG and various ROEs, do not clearly exceed the requirements of international law or exclusively reflect non-legal considerations of morality, politics, and military strategy. Instead, I propose that these targeting policies are best understood, at least in part, as efforts to mitigate legal risk.

Every lawyer advising a client must ask herself at least two questions. First, in my professional judgment, what is my client required to do, permitted to do, and prohibited from doing? Second, what if my professional judgment is wrong, or others (courts, regulators, partners, competitors) disagree? In other words, what legal risk does this course of action bring with it, are those legal risks justified, and how might they be minimized?

Thus, even if the U.S. government believes that current targeting policies exceed the requirements of international law, it should consider the risk that future Administrations, other States, international bodies, and other institutions will disagree. Before modifying or abandoning current targeting policies, the current Administration should carefully weigh the legal risks of doing so, in addition to moral, political, and strategic considerations.

Relatedly, where the U.S. interpretation of international law differs from the interpretation of our coalition partners, often the more restrictive interpretation will, as a practical matter, prevail. Presumably, our coalition partners will not assist U.S. military operations, let alone participate in joint operations, that violate their interpretation of international law. As Ryan Goodman and others have explained, such cooperation would entail prohibitive legal risks for them.

In this post, I will focus on the targeting rules contained in the 2013 Presidential Policy Guidance (PPG) and reaffirmed in the 2016 Legal and Policy Frameworks (LPF). These rules apply outside what the PPG calls “areas of active hostilities,” such as Afghanistan, Iraq, and Syria. I hope to discuss the rules applicable inside these areas in a future post. However, since Al Qaeda, ISIS, and their affiliates operate both inside and outside these areas, the PPG and LPF warrant separate discussion. 

The PPG and LPF “set forth a series of policy conditions that are more restrictive than the law of armed conflict requires that must be met before such force will be used,” including that:

  • The United States will use lethal force against only a terrorist target that poses “a continuing, imminent threat to U.S. persons,” underscoring that it is simply not the case that all terrorists overseas pose such a threat;
  • Before lethal action may be taken, the United States must have “near certainty” that the terrorist target is present;
  • Before lethal action may be taken, the United States must have “near certainty” that non-combatants will not be injured or killed;
  • There must be an assessment that the capture of the target is not feasible at the time of the operation and that no other reasonable alternatives exist to address the threat to U.S. persons effectively; and
  • Lethal action requires an assessment that relevant governmental authorities in the country where the action is contemplated either cannot or will not effectively address the threat to U.S. persons.

In fact, these “policy conditions” help to ensure that U.S. operations conform to mainstream interpretations of international law—interpretations that the United States may not share, but that other States and international bodies might apply to U.S. conduct.

Continuing, Imminent Threat

The United States takes the view that the law of armed conflict does not, as such, prohibit attacks on members of organized armed groups with which we are in armed conflict, irrespective of their specific function or current conduct. On this view, formal membership alone—i.e., having pledged to follow orders of the armed group—is enough to make an individual a lawful target at any time.

In contrast, the ICRC takes the view that functional membership is required to make an individual a lawful target at any time. On this view, only individuals whose continuous function is to participate in hostilities on behalf of an armed group are targetable irrespective of their current conduct. By requiring that targeted individuals must pose a continuing or imminent threat—by planning, preparing, or executing attacks—the PPG likely ensures that U.S. action will prove lawful on either view.

In addition, some States, courts, and experts take the view that international human rights law applies to the extraterritorial use of lethal force, at least outside areas of active hostilities, and prohibits the intentional killing of individuals who do not pose an immediate threat. The United States seems to disagree. Regardless of who is right about the legal question, application of the PPG ensures that the requirements of human rights law, as applied to the factual circumstances in question, are satisfied.

Finally, where the United States does not have the consent of the territorial State to conduct military operations on its territory, the existence of a continuing, imminent threat may be required to justify the infringement of the territorial State’s sovereignty under the UN Charter and the customary jus ad bellum. In these cases, the PPG may not exceed the requirements of international law even on the U.S. government’s own view.

Near Certainty of the Target’s Identity and Legal Status

Under Additional Protocol I, attackers must consider persons civilians in cases of doubt. While the United States is not a party to Protocol I, many of our coalition partners are parties, and apply its provisions in both international and non-international armed conflict. Accordingly, these coalition partners may not participate or assist in military operations that violate its provisions. Importantly, the PPG likely ensures that U.S. operations will conform to the Protocol I standard.

For its part, the Department of Defense has taken the extreme view that, “[u]nder customary international law, no legal presumption of civilian status exists for persons or objects.” That extreme view is probably incorrect, for reasons that have been sketched elsewhere (see here and here).

To be fair, there remains some debate over the correct formulation of the customary law standard. According to one group of experts, “[t]he degree of doubt necessary to preclude an attack is that which would cause a reasonable attacker in the same or similar circumstances to abstain from ordering or executing an attack.” Alternatively, according to the ICRC, “this determination will have to take into account, inter alia, . . . the urgency of the situation, and the harm likely to result to the operating forces or to [civilians] from an erroneous decision.” Since a reasonable attacker will likely take precisely these considerations into account, the two formulations may end up generating similar conclusions.

On either view described above, international law may require a high degree of certainty that an intended target is a lawful target prior to attack (a) when the situation is not urgent since an equally effective attack may be carried out later and (b) harm is unlikely to result to operating forces or civilians from an erroneous decision to refrain from attack. Accordingly, substantial doubt that the intended targets have been properly identified may often prove sufficient to preclude lawful attack. The PPG ensures that U.S. operations will conform to this understanding of international law, even if the U.S. government does not accept that understanding itself.

The PPG also provides that U.S. operators “must employ all reasonably available resources to ascertain the identity of the target.” According to the ICRC, customary international law requires attacking forces to do everything feasible to verify that their intended targets are not protected civilians but combatants or direct participants in hostilities. The U.S. legal position on this point is somewhat ambiguous, as I’ve explained elsewhere. In any event, the PPG would seem to satisfy the likely customary standard, with which the U.S must comply in any case.

Near Certainty That Noncombatants Will Not Be Injured or Killed

Many experts believe that human rights law applies to extraterritorial uses of force outside areas of active hostilities and flatly prohibits knowingly or foreseeably killing individuals who pose no immediate threat. This view is probably too strong, at least outside of traditional law enforcement contexts, but it cannot be rejected out of hand. In any event, even if the United States does not accept this view, the PPG ensures that U.S. operations will conform to human rights law in any case.

The United States accepts that the law of armed conflict requires attacking forces to delay launching an attack whenever  doing so is militarily feasible and will avoid or reduce unintended harm to nearby civilians. Outside so-called “areas of active hostilities,” such precautions may often prove militarily feasible, as there may be little or no military disadvantage to postponing attack until there are no civilians in harm’s way.  Compliance with the PPG ensures that this precautionary rule is satisfied.

International law also prohibits attacks likely to inflict harm on civilians that would be disproportionate or excessive in relation to the concrete and direct military advantage reasonably anticipated. The military advantage of killing a particular combatant depends, in turn, not simply on his role in an opposing force but also on the measurable impact that killing him will have on the collective threat posed by the opposing force before he will be effectively replaced. In areas of active hostilities, it may be possible to kill members of the opposing force faster than they can be effectively replaced, such that all or most such killings yield a substantial military advantage. However, outside areas of active hostilities, the military advantage of isolated or sporadic strikes may be insufficient to justify collateral harm to civilians. By requiring near certainty that no civilians will be killed or injured, the PPG ensures that the lawfulness of U.S. military action will not depend on speculative estimates of military advantage. Put another way, the PPG may simply require what international law—applied to the relevant factual circumstances—requires in any case.

Not Feasible to Capture

Many experts believe that human rights law applies to extraterritorial uses of lethal force, including during armed conflict and inside areas of active hostilities, and prohibits intentionally killing individuals whom it is feasible to capture or arrest:

Where military necessity does not require parties to an armed conflict to use lethal force in achieving a legitimate military objective against otherwise lawful targets, but allows the target for example to be captured rather than killed, the respect for the right to life can be best ensured by pursuing this option.

Even if the United States does not accept this view, the PPG ensures that U.S. operations will conform to this standard in any case.

Similarly, the ICRC takes the view that the law of armed conflict itself prohibits killing a lawful human target who may easily be captured. On this view,

while operating forces can hardly be required to take additional risks for themselves or the civilian population in order to capture an armed adversary alive, it would defy basic notions of humanity to kill an adversary or to refrain from giving him or her an opportunity to surrender where there manifestly is no necessity for the use of lethal force.

The United States rejects this view of the law of armed conflict. Nevertheless, the PPG ensures conformity with the international law on either view.

Finally, the law of armed conflict requires attackers to take feasible precautions in planning and carrying out attacks so as to avoid or reduce harm to civilians. Accordingly, the precautions rule may effectively require capture of lawful human targets when (a) there remains some doubt that the intended targets have been properly identified or (b) an attempt to capture them would be substantially less likely to kill or injure nearby civilians than a lethal strike. Since “near certainty” that a human target has been properly identified and that no civilians will be harmed by a strike still admits of some doubt, the law of armed conflict may require an attempt to capture when doing so would not endanger attacking forces. The PPG ensures lawful conduct no matter how these questions are resolved.

Territorial State Cannot or Will Not Effectively Address the Threat

Finally, where the United States operates without the consent of the territorial State, it would violate the UN Charter and the customary jus ad bellum to use lethal force if the territorial State is willing and able to address the threat itself. The United States accepts this view, and the PPG ensures conformity with it.


Before recommending changes to U.S. targeting policies, inside or outside areas of active hostilities, the Secretary of Defense should not rely exclusively on the U.S. government’s own  understanding of international law. What we may view as mere “policy,” other States, international bodies, and, indeed, courts may view as legal obligations in many circumstances. Accordingly, the legally safer course of action may be to retain existing targeting policies that exceed the requirements of international law as the U.S. government understands them, but that may simply reflect the requirements of international law as others understand them. Our targeting policies should reflect not only moral, political, and strategic considerations but also a sober recognition of the legal risk that our understanding of international law is both fallible and controversial.

Image: U.S. Department of Defense