Targeting Jihadist Terrorists: Identifying Pertinent Legal Guidelines Commentary
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Targeting Jihadist Terrorists: Identifying Pertinent Legal Guidelines

Targeted killing campaigns are still accelerating under the Trump administration, with fewer constraints and even less transparency. More precisely, it seems that the Obama-era Presidential Policy Guidance has been relaxed in two very meaningful ways: targets of “kill missions” are being expanded to include more Jihadist “Foot Soldiers” (rather than just identifiable terrorist leaders) and directed drone attacks will no longer go through any high-level vetting. In this connection, the pertinent theaters of active hostilities are primarily Afghanistan, Iraq, Syria, Yemen and Somalia. The latest Authorization for Use of Military Force (AUMF) permits the president to target ISIS, al-Qaeda, or “associated forces” at any time. Significantly, there is no corollary obligation for the president to define publicly either the targeted terrorist forces or the geographic areas of targeted attack. Also worth noting is the undeclared United States war on terror now underway in West Africa. There are good legal reasons to recall that President Trump has openly urged the targeted killing of terrorist families (wives, mothers, children, etc.) as well as alleged terrorists themselves.  To this point, there is little if any reliable data to support the tactical benefit of any Trump-era targeted killings. Finally, especially worth noting here is that President Trump recently designated the Iranian Revolutionary Guard Corps a terrorist group. Should he begin to authorize targeted assassinations of these official regime military forces, it could be taken prima facie in Tehran and elsewhere as an instance of US aggression.

Under the protective tutelage of any American president, “We the People” should expect basic safety in world politics. At a minimum, we should be able to assume that wider and capable circles of public authority remain ready to thwart terrorist attacks.  More specifically, such assurances should apply with special clarity to mega-terrorist attacks involving chemical, biological or nuclear threats. In terms of United States law, the authoritative roots of any such presumptive and indispensable assurances go back to the seventeenth century English philosopher, Thomas Hobbes.

Though unfamiliar to America’s current president, Thomas Hobbes’ Leviathan was plainly integral to the education of Thomas Jefferson. The duly celebrated author of the Declaration was himself widely read; he cared very considerably about serious and dignified learning. In contrast to Donald J. Trump’s current inversion of US policy-making priorities, our third president believed expressly in the primacy of “preparation”, and not of mere “attitude”.

Regarding US counterterrorist preparation, America’s national security establishment must get ready for absolutely all contingencies. This includes, of course, building the conceptual foundations for any future Osama Bin-Laden “elimination-type” operations. During the Obama years, one major targeted killing of a Jihadist terrorist was the September 2011 US drone-assassination of Anwar al-Awlaki in Yemen. That particular case was notably “special” in one frequently overlooked aspect: The Jihadist al-Awlaki was born in New Mexico, and was ipso facto a US citizen.

Notwithstanding the US Constitution’s Fifth Amendment protections concerning “due process,” it was a tactical posture that might sometimes need to be repeated.

What then? In relevant jurisprudential terms, what precise legal guidelines would we Americans want followed? To respond properly (among several other related and also intersecting concerns), Mr. Trump and his designated counselors would then need to inquire: Is it sufficiently legal to target and kill such terrorists if suitably precise linkages between prospective targets and discernible attack intentions can be documented?”

To meaningfully answer this core question, it will first be necessary for Mr. Trump’s national security officials to ask whether a proposed terrorist killing plan would be gainfully preemptive or just narrowly retributive. If only the latter, a judgment wherein national self-defense was not in any way the underlying action rationale, authoritative determinations of legality could become substantially more problematic.

It gets even more complicated. Under Executive Order No. 12333 assassination is explicitly prohibited.  It is also generally a crime under international law which, though not widely understood, is a tangible part of American domestic law as we learn from The Paquete Habana. Still, at least in certain more-or-less residual circumstances, the targeted killing of Jihadist terrorist leaders could be correctly excluded from ordinarily prohibited behaviors. Thereby, such peremptorily protective actions could still be defended as a permissible expression of national law-enforcement.

A similar defense might sometimes be applied to the contemplated killing of terrorist “rank-and-file,” especially where such selective lethality had already become part of an already-ongoing pattern of US counter-terrorism. For example, the United States had earlier widened the scope of permissible terrorist targeting in parts of Iraq, Afghanistan, and Syria. In part, such a widened arc of permissibility – one which now modifies more stringent prior rules of engagement that had once required specific human target identifications – has represented a byproduct of continuously developing technologies.

Most obvious, among these newer technologies, is growing US reliance upon drone-based assassinations, and also on certain other related forms of long-range or distant killing.

In the best of all possible worlds, of course, there would be no need for any such decentralized or “vigilante” expressions of international justice.  Conspicuously, of course, we don’t yet live in such an ideal world. Instead, enduring uneasily in our present and still-anarchic world legal order – a context that we international law professors prefer to call “Westphalian” – the only real alternative to precise self-defense actions against terrorists is likely to be worsening battlefield instabilities. Ultimately, such expanding hyper-instabilities could include even more flagrant and consequential escalations of Jihadist terror-violence.

At some indeterminable point, such escalations could lead to unprecedented instances of chemical, biological or nuclear attack. These attacks might be undertaken by assorted sub-state adversaries or instead, by certain “hybrid” combinations of state and sub-state foes. Ironically, in policies of US ally Israel, the dominant concern remains Iran-Hezbollah and/or Iran/Hamas combinations.

The evident irony here stems from the fact that one Iranian surrogate (Hezbollah) is Shiite, while the other (Hamas) is Sunni.

At the most basic level of such issues and calculations, the very idea of assassination or targeted killing as remediation seems paradoxical, almost an oxymoron.  Seemingly, this understandably objectionable idea must preclude the input of all the more usual due processes of law. Yet, since the current or “Westphalian” state system’s original inception in the seventeenth century, international relations have never been governable by the same civil protections that are potentially available within democratic states.

In this persistently anarchic and prospectively chaotic world legal system, one which still lacks any duly-constituted and effective supra-national authority, assorted Jihadist leaders (ISIS, Hamas, Hezbollah, Islamic Jihad, al-Qaeda, etc) are already responsible for the mass killing of noncombatant men, women, and children of many different nationalities. It follows that wherever such leaders are not suitably “terminated” by the United States or by any of America’s key allies (e.g., Israel, in the tumultuous Middle East), blatantly egregious terror crimes will almost certainly (1) continue and (2) be left unpunished. Any such predictable de facto impunity would be inconsistent with the universal legal obligation to punish international crimes, a jus cogens or peremptory obligation reaffirmed at the original Nuremberg Tribunal and subsequently in the Nuremberg Principles.

More formally, this lex talionis obligation, which comes to us from both ancient Roman law and the Hebrew Bible, is known formally and correctly as Nullum crimen sine poena, or “No crime without a punishment.”

Inevitably, complex considerations of law and tactics must inter-penetrate. In this particular connection, the glaring indiscriminacy of most jihadist operations is rarely if ever the result of enemy inadvertence. Rather, it is typically the intentional outcome of violent terrorist inclinations, unambiguously murderous ideals that lay deeply embedded in the Jihadist terrorist leader’s operative view of insurgency.

For Jihadists, there can never be rendered any meaningful distinction between civilians and non-civilians, between innocents and non-innocents. For these active or latent terrorist murderers, all that really matters are certain unassailable and immutable distinctions that distinguish between Muslims, “apostates”, and “unbelievers.”

As for the apostates and unbelievers, it is all quite simple.  Their lives, believe the Jihadists, have no value. Prima facie, that is, they have no immunizing sanctity.

In law, international and national, every government has both the right and the obligation to protect its citizens against external harms. In certain circumstances, moreover, this coincident right and obligation may extend derivatively to targeted killing. This point has long been understood in Washington, where every president in recent memory has given nodding or substantially more direct approval to “high value” assassination operations.

Generally, assassination is a certifiable crime under international law. Yet, in our essentially decentralized system of world law, self-help by individual states is still often necessary, and is more-then-occasionally the only real alternative to passively suffering terrorist crimes. In the absence of certain particular targeted killings, terrorists could continue to create havoc against defenseless civilians almost anywhere, and with complete impunity.

A basic difficulty here is that Jihadist terror criminals are usually immune to the more orthodox legal expectations of extradition and prosecution (Aut dedere, aut judicare). This is not to suggest that the targeted assassination of terrorists will always “work” – there is literally nothing to support the logic of any such suggestion – but only that disallowing such targeted killing ex ante could not be operationally gainful or legally just.

If carried out with aptly due regard for pertinent “rules”, assassinating terrorist leaders could remain consistent with the ancient legal principle of Nullum crimen sine poena (“no crime without a punishment”). Earlier, this original principle of justice had been cited as a dominant rationale for both the Tokyo and Nuremberg war crime tribunals. Accordingly, it was subsequently incorporated into law through international custom, consistent with Article 38(1)(b) of the Statute of the International Court of Justice.

By both the codified and customary standards of contemporary international law, all terrorists are Hostis humani generis, or “Common enemies of humankind.”  In the fashion of pirates, who were to be hanged by the first persons into whose hands they fell, terrorists are international outlaws who fall within the scope of “universal jurisdiction.” But choosing precisely which terrorists ought to be targeted remains a largely ideological rather than jurisprudential matter.

In some current circumstances, tyrannicide could be seen as the logical “flip side” of American counter-terrorism. Historically, limited support for expressing assassination as a form of tyrannicide is not hard to discover.  It can be found for example in classical writings of Aristotle, Plutarch and Cicero.

Overall, in his consideration of assassination or targeted-killing as counter-terrorism, President Trump (or more realistically his designated counselors) should consider the clarifying position of Swiss scholar Emmerich de Vattel in his most famous work, The Law of Nations, or the Principles of Natural Law (1758): “The safest plan is to prevent evil where that is possible. A Nation has the right to resist the injury another seeks to inflict upon it, and to use force and every other just means of resistance against the aggressor.”

Earlier, a similar view had been presented by Samuel Pufendorf in his text, On the Duty of Man and Citizen According to Natural Law (1682):

“Where it is quite clear that he is engaged in planning violence against me, even though he has not fully revealed his design, I shall be justified in immediately initiating self-defence by force, and in seizing the initiative against him, while he is still making preparations…..The aggressor will be taken to be the party which first conceived the intention to harm the other….To have the name of defender, it is not necessary to suffer the first blow, or merely to elude and repel the blows aimed at one.”

Even earlier, the right of self-defense by forestalling an attack had been established by the foundational Dutch scholar, Hugo Grotius, in Book II of The Law of War and Peace (1625). Recognizing the need for what later jurisprudence would reference as threatening international behavior that is “imminent in point of time” (See The Caroline Case, 1837), Grotius indicated that self-defense must be permitted not only after an attack has already been suffered, but also in advance, where “the deed may be anticipated.”

Further on, in the same chapter, Grotius summarized: “It be lawful to kill him who is preparing to kill.”

Interestingly, Vattel, Pufendorf and Grotius were all taken into primary account by Thomas Jefferson, in his critical fashioning of the American Declaration of Independence.

In a far better world than this one, assassination could have no defensible place as counterterrorism, either as a preemptive measure or ex post facto, that is, as a permissible retribution. But, as if anyone should still need a reminder, we do not yet live in the best of all possible worlds, and the obviously negative aspects of targeted killing should never be evaluated apart from the foreseeable costs of all other available options. More precisely, such aspects should always be closely compared to what could be expected of all plausible alternative choices.

International law is not a suicide pact. Ubi cessat remedium ordinarium, ibi decurritur ad extraordinarium; “Where the ordinary remedy fails, recourse must be had to an extraordinary one.”

President Trump is correctly expected to comply with the rules and procedures of humanitarian international law, yet he must also continue to bear in mind that Jihadist enemies will remain unaffected by these or any other jurisprudential expectations. Assassination and other still broader forms of preemption may sometimes be not only allowable under binding international law, but also indispensable. Conversely, however, there are occasions when strategies of assassination could be determinedly legal but remain operationally ineffectual.

Recalling the close connections between international law and US law – connections that extend to direct and literal forms of “incorporation” – an American president can never choose to dismiss the law of war on grounds that it is “merely international.”  Always, President Trump should consider decipherable connections between assassination, counter-terrorism and United States Constitutional Law.  Recall that the targeted killing of Anwar al-Awlaki had been approved by US President Barack Obama and by a still-secret committee of advisors based in the US Department of Justice.

Under US law, we are now bound to inquire whether an American president should ever be authorized to order the extra-judicial killing of a United States citizen – even one deemed an “enemy combatant” – without any at least perfunctory reference to “due process of law?” On its face, any affirmative response to this necessary query would be difficult to defend under the US Constitution.

Of necessity, such approval would need to be based upon a reasonably presumed high urgency of the terror threat posed by the prospective victim. Any such allegedly “authorized” targeted killing of US citizens would express a potentially irremediable tension between theoretically indissoluble individual citizen rights and the increasingly peremptory requirements of public safety.

US policy on assassination or targeted killing will have to reflect a very delicate balance. Most important, in any such calculation, will be the protection of civilian populations from Jihadist terror-inflicted harms. In those circumstances where such harms would involve unconventional weapons of any sort – chemical, biological or nuclear – the legal propriety of targeting Jihadist terrorists could be patently obvious and effectively “beyond reasonable doubt.”

Nonetheless, such proper legal assessments ought never be undertaken apart from corresponding operational expectations. This means, inter alia, that before any “extraordinary remedies” should be applied, those presumptive remedies should be not only legal, but also tactically sound. In the end, we may now be reminded by Cicero, “The safety of the people shall be the highest law.”


Louis René Beres was educated at Princeton (Ph.D., 1971), and is the author of many books and articles dealing with history, law, literature, and philosophy. He was born in Zürich, Switzerland, at the end of World War II. Some of his pertinent publications have appeared in JURIST; Harvard National Security Journal (Harvard Law School); Yale Global Online; Parameters: Journal of the US Army War College; Special Warfare (Pentagon);  Armed Forces and Society; Bulletin of the Atomic Scientists; The Strategy Bridge; Israel Defense (Tel Aviv); BESA Perspectives (Tel Aviv);  INSS Strategic Assessment (Tel Aviv); The War Room (Pentagon); Infinity Journal (Tel Aviv); Modern War Institute (West Point); International Security (Harvard); World Politics (Princeton); and Oxford University Press.


Suggested citation: Louis René Beres, Targeting Jihadist Terrorists: Identifying Pertinent Legal Guidelines JURIST – Academic Commentary, May 17, 2019,




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