This article is the latest in our Fog of Law series that examines the gray zones in international law and conflict that can be exploited by states. The series comes in advance of an expert workshop on the topic at the US Naval War College’s Stockton Center that Just Security is cosponsoring with the Naval War College and the International Committee of the Red Cross.

Many contemporary security operations against nonstate actors occur at the intersection of international humanitarian law (IHL) and international human rights law (IHRL). This area of international law is volatile and contentious—a point that should not be controversial but, as I explained here, often gets lost in the conversation. My goals in this article are, first, to describe this legal terrain and, second, to assess the options for dealing with it.

Discordance in the Law

Start with IHL. Before applying IHL, one must decide, as a threshold matter, whether the operation at issue is part of an armed conflict. The decision is sometimes straightforward; an armed conflict either exists or does not. But many contemporary operations are conducted in situations for which the armed conflict designation is unclear. For example, although most IHL experts would accept that the United States is in an armed conflict against the so-called Islamic State in Iraq and Syria (ISIS), the geographic scope of the conflict is contested. The extent to which IHL governs U.S. operations against ISIS in places other than Iraq and Syria is unsettled.

Further, whenever IHL applies, its substantive content is often contested. The key IHL treaties were designed primarily for interstate wars, so they contain only sparse provisions for most conflicts involving armed nonstate groups—what are known as “non-international armed conflicts.” Many IHL experts, including the ICRC, posit that customary IHL fills the treaty “gaps” by establishing for all conflicts a set of norms that are modeled after the treaty law for international conflicts. Although that proposition is widely accepted at a high level of generality, experts fundamentally disagree about how to translate for non-international conflicts the law that was designed for international conflicts. Their divisions were evident, for example, when the ICRC adopted its 2009 Interpretive Guidance on the Notion of Direct Participation in Hostilities. The ICRC meant for the Interpretive Guidance to settle an issue that lies at the heart of IHL: when may someone be targeted for attack? Instead, it generated a sharp debate on that question.

Meanwhile, many global actors resist the idea that customary IHL, as modeled after the treaty law for international conflicts, is the appropriate regulatory framework for these operations. When national courts, human rights institutions, and civil society groups appraise contemporary security operations, they often disregard IHL or apply hybrids that mix IHL with other sources. U.S. courts usually apply domestic law, as vaguely informed by IHL, rather than IHL itself. The Israeli Supreme Court has applied a blend of domestic and customary IHL. And the European Court of Human Rights has repeatedly applied IHRL, instead of IHL, to situations that are also covered by IHL. IHL purists might insist that these decisions are external to and not reflective of IHL proper. But the decisions shape IHL’s content and relevance in concrete settings. They affect what international law means in those settings.

A similar set of questions appear on the IHRL side of the ledger. As discussed, human rights institutions periodically assess the security operations that states conduct against nonstate actors. Yet their decisions tend to be incremental, fact-specific, and at times even contradictory. As such, there continue to be heated debates about the scope of application and substantive content of IHRL outside paradigmatic law enforcement settings—particularly where states conduct security operations in other states or during declared emergencies.

To be clear, I am not suggesting that this area of international law is entirely up for grabs. It is not. Some norms, like the prohibition of torture, are strong and settled. These norms are at times violated, and their content is in peripheral cases unclear, but they are, at their core, widely accepted and treated as law. For example, no one seriously contends that transmitting high-voltage electric shocks to a detainee’s genitals can ever be internationally lawful. Further, even in the zones of contestation—where the law’s content is unsettled—many legal positions are out of bounds. A state plainly may not target to kill someone just because she happens to live near a suspected terrorist. The point is that, as applied to contemporary security operations, much of IHL and IHRL are characterized not by clarity and settlement but by fluidity and contest.

Legal Strategies

Lawyers and policymakers have no choice but to operate in this space. Below, I identify and assess four legal strategies that they use. These strategies are not mutually exclusive; an analyst might use two or more of them in a single episode. But they can be in tension with one another. And they are not all equally effective or suitable for every situation. Teasing them out should help us be more deliberate about our own choices and clearheaded when we evaluate what others are up to.

(1) Try to Settle the Law

One strategy is to try to settle the law’s substantive content. This strategy can work well at a granular level. For example, a regional human rights court that assesses an operation authoritatively resolves what the applicable IHRL treaty requires in the case at hand. To the extent that the court’s reasoning is generalizable, rather than confined to the particular facts, it can also shed light on what the treaty requires in similar cases. Likewise, when a multilateral coalition establishes shared rules of engagement for a field of operations, it determines, even if only implicitly and in the first instance, what international law means there. The rules of engagement might also shape how coalition members think about or apply the law in other fields.

Many international lawyers try to employ the same strategy at higher levels of abstraction; they try to clarify the law for entire categories of cases. The ICRC’s Interpretive Guidance is one example. Such efforts face an uphill battle because the international legal system at the intersection of IHL and IHRL is highly decentralized. No one actor or institution has the authority to settle the law, so as long as key participants have fundamentally incompatible positions on the law, the discordance and instability are likely to persist.

To illustrate, consider again a regional human rights court. The court’s position on the law can have ripple effects outside the regional system, as actors that agree with it treat it as persuasive authority and seek to extend its reach. But if the position is highly contentious, it is unlikely to settle the law. Those who disagree with it will use the law’s fluidity to undercut it. States that are part of the regional arrangement might respond by derogating from the relevant treaty provision. They might retreat from the court’s jurisdiction. They might “outsource” their questionable operations to other states. Or they might expressly challenge the court’s ruling as wrong on the merits. Meanwhile, actors that are not part of the regional arrangement can easily ignore or discount what the court has said. All of this is par for the course because the court lacks authority to resolve what IHL and IHRL require as a general matter.

Thus, in the zones of contestation, positions on the law that are endorsed by some actors are routinely resisted and undermined by others. These positions are accepted and treated as law only provisionally, for discrete operations, by some actors, or in particular venues. And efforts to treat them as dispositive—as settling the law across the board—will not work.

(2) Pretend the Law is Clear

A second strategy is simply to ignore the contest and pretend that the law is clear—or more precisely, that the law is what the person who invokes it wants it to be. The United States and its critics have both used this strategy in the context of U.S. lethal operations against suspected terrorists. The United States has consistently claimed that it is in a borderless armed conflict against various jihadi groups and that IHL governs its drone strikes against members of these groups. There is little doubt that IHL applies to U.S. strikes in hot warzones. But recall that there are heated debates about which situations qualify as warzones and the extent to which IHL applies outside of them. As such, the U.S. claim that IHL necessarily governs all of these operations does not accurately reflect the law. The law is more contingent, qualified, and unsettled than that claim admits.

The same can be said of the usual retort to the U.S. claim. Many human rights advocates contend that, outside actual warzones (however defined), international law requires the United States to conform to the standards for ordinary law enforcement operations under IHRL. This claim is, like the U.S. one, overdrawn. As I have explained before, the IHRL standard for using lethal force is highly context-dependent, not one-size-fits-all. Human rights institutions apply IHRL more loosely—and afford states more discretion to kill—when a situation is chaotic, and the state has little operational control, compared to when it conducts an ordinary law enforcement operation in its own territory. So, even assuming that IHRL governs U.S. lethal operations, it doesn’t necessarily require the same thing of the United States in Somalia as it does in Cincinnati. The claim that it does is, again, a distortion of the law, not an accurate reflection of it.

Pretending that the law is clear can at times be good legal strategy. It is routinely used by lawyers in advocacy roles—those who seek to advance their own preferences on the law or who are in the position of justifying a client’s conduct. However, the strategy is not suitable for those in more analytic or advisory positions. Lawyers who are asked to explain the law in confidence or to advise neutral arbiters on what position to take on the law would do well to acknowledge the uncertainty and contest that actually exist. If they do not, they will mislead their interlocutors into thinking that the law is more certain than it is. A client would rightly be upset if, after relying on her lawyer, she finds unexpectedly that her legal position lacks traction in important venues or is under attack by key constituencies. Had she been informed of those eventualities, she might have adopted a different or more nuanced position.

(3) Identify Core Substantive Principles

Another strategy is to try to identify common principles that cut across the existing international rules on an issue and then to use those principles to inform decisions when none of the rules is directly on point. I myself have advocated for this strategy for operations to target to kill or preventively detain nonstate actors. I claimed that the existing rules on targeting and detention were designed for particular scenarios—operations that are conducted either in law enforcement settings, during national emergencies, against lawful combatants, or against civilians in wartime. These rules require different things, depending on the context in which a state acts. But, I argued, certain core principles animate all of them. Thus, where none of the rules applies by its own terms in a given situation, one might resist the impulse to pick the best of the bad options and simply transpose it to that situation. One might instead revert to the core principles and craft a legal position that is better tailored to the facts.

Flexible legal principles like the ones that I identified require the exercise of discretion, so they do not definitively establish whether particular operations are or are not lawful. Global actors with different priorities can use the same principles to push for contrary results. Thus, the strategy is not a way to resolve the law’s content in the face of an ongoing normative contest.

Yet if one accepts that the law is already discordant, focusing on the substantive principles that animate all of it can be fruitful. This strategy allows lawyers to move past the legal tangle and more accurately and cleanly describe the law—if not the outcome of every decision, the overall trends in and expectations about the law. Lawyers can therefore use this strategy to provide a bird-eye view of the law and guidance in developing broad-based legal and policy positions.

The strategy can also be an effective advocacy tool. Rather than argue that this or that ill-fitting rule “clearly” applies, a lawyer might recognize the law’s openness in the situation at hand, identify the principles that animate the law for other settings, and then use those principles to argue for a position that is suitable for the facts. Because the principles are flexible, a lawyer who uses this strategy might not get exactly the outcome that she desires. But she might get closer to that outcome with this approach than by invoking a more extreme position and pretending that it is already law.

Finally, focusing on a set of common principles enables experts who are squarely in the IHL or the IHRL camp to communicate with one another without crossing into the other domain. Put differently, it helps them move beyond their own epistemic communities. So, it creates the conditions for them to find pockets of agreement and then try to stabilize the law in those areas.

(4) Demand Information and Justification

A fourth strategy is to demand that states disclose information about and provide the legal grounds for their security operations. This strategy is often a precursor to one of the others and critical to holding the state accountable. If we don’t know what the state is doing, we can’t quite analyze or even argue about whether it is acting lawfully. The strategy is also valuable for something like its own sake. A key component of the rule of law is that official decisions be publicly justified and subjected to external scrutiny. If nothing else, that dynamic invites people to engage critically with and participate in the governance decisions that affect them. Because the U.S. government has, in the Trump Administration, been noticeably less transparent about its security operations, now might be a good time to double down on this strategy.


Lawyers and policymakers who are uncomfortable with the law’s volatility tend to use the first and second strategies—to try to correct it or pretend it is not there. Those strategies are sometimes appropriate and effective. But they are not always, and even when they are, they are not necessarily the best or only options. Those who have to operate in this space ought to start with a clear vision of it and then be deliberate in deciding how to navigate it.