There is little doubt that jihadi terrorism will continue to accelerate in 2025. For the United States and Israel, this means, inter alia, an accelerated reliance on targeted killings of terrorist leaders. Such anticipated reliance would not be unlawful. On the contrary, by reaffirming basic principles of national self-defense in an anarchic world, it would be distinctly law-enforcing.
Still, there will be codified and customary legal guidelines. To meaningfully proceed on this task, it will first be necessary for American and Israeli decision-makers to inquire whether a terrorist-killing plan would be gainfully pre-emptive or narrowly retributive. Additionally, all judgments concerning targeted killing as counterterrorism would have to meet tactical and legal goals. It would not be sensible, after all, to launch risky defensive actions against murderous terrorist adversaries solely because these actions could satisfy pertinent legal standards.
It will get even more complicated. Assassination is expressly prohibited by United States law. It is also generally a crime under international law, which is a part of American domestic law. Nonetheless, in defensive circumstances, the targeted killing of jihadi terrorist leaders would be excluded from ordinarily prohibited behaviors. A similar argument could be applied to considered killings of terrorists “rank-and-file,” especially where selective lethality is already part of an ongoing pattern of essential counterterrorism.
In the best of all possible worlds, there would be no need for any “vigilante” forms of justice. However, we don’t yet live in such a world. If left to their own consistently criminal intentions, jihadi terrorists could ultimately invoke the use of weapons of mass destruction.
In principle, the idea of assassination or targeted killing as remediation is paradoxical. Since the current state system’s inception in the 17th century, international relations have never been governed by the civil protections available in democratic states. It follows that when such countries as the United States and Israel are confronted with potentially existential threats, they have a natural right to extreme self-defense. Moreover, under rules that come originally from ancient Jewish law and the later (1946) Nuremberg Principles, there should be “no crime without a punishment.”
For the United States and Israel, variously complex considerations of law and tactics will intersect. The indiscriminacy of jihadist operations is rarely the result of adversarial inadvertence. Rather, it is the intentional outcome of violent terrorist inclinations and murderous ideals that lie embedded in a jihadist terrorist leader’s operative views of insurgency.
For jihadists, there are no meaningful distinctions between civilians and non-civilians, innocents and non-innocents. For these active or latent terrorist murderers, all that matters are the unassailably immutable distinctions between Muslims, “apostates” and “unbelievers.”
As for the apostates and unbelievers, it is quite simple. Their lives, the jihadists believe, have no value. Prima facie, they have no immunizing sanctity. In law, both international and national, every government has the right and obligation to protect its citizens against external harm. In certain derivative circumstances, this coincident right and obligation may extend to targeted killing.
Usually, assassination is a crime under international law. Yet, in our decentralized system of world law, extraordinary self-help by individual states is often necessary. In the absence of particular, targeted killings, terrorists would continue to create havoc against defenseless civilians almost anywhere of their choosing and with unjust impunity.
A basic difficulty for imperiled states is that jihadi criminals are indifferent to orthodox legal expectations of extradition and prosecution. This is not to suggest that the targeted killing of terrorists will always “work,” but only that disallowing such killing ex-ante would not be operationally gainful or legally just.
By the authoritative standards of contemporary international law, all terrorists are hostes 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.” Said Swiss scholar Emmerich de Vattel in The Law of Nations (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.”
Even earlier, the right of self-defense by forestalling an attack was asserted by foundational Dutch scholar, Hugo Grotius, in book II of On The Law of War and Peace (1625). Recognizing the need for what later jurisprudence would reference as threatening behavior that is “imminent,” Grotius indicated that self-defense is permitted not only after an attack has already been suffered, but also where “the deed may be anticipated.” In the same chapter, he summarized, “It be lawful to kill him who is preparing to kill.”
In a better world than the one we inhabit, targeted killings could have no defensible place as counterterrorism, either as a pre-emptive measure or 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 negative aspects of such killings ought never to be evaluated apart from the foreseeable costs of other available options. Such aspects should be closely compared to what could be expected of plausible alternatives.
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.”
Israel and the United States are obligated to comply with the rules and procedures of humanitarian international law; however, both must also bear in mind that jihadist enemies will remain unaffected by these expectations. Targeted killings and broader forms of pre-emption are sometimes not only allowable under binding international law but also required. Conversely, there are occasions when assassination could be determinedly legal but still be operationally ineffectual.
Under U.S. law, we are bound to inquire, should an American president ever be authorized to order the extra-judicial killing of a United States citizen, even one deemed an “enemy combatant” without reference to due process of law? Any affirmative response to this query would be difficult to defend under the U.S. Constitution. Operational approval would need to be based upon a reasonably presumed high urgency of a terror threat. Any such “authorized” targeted killing of a U.S. citizen would express potentially irremediable tension between fundamental citizen rights and indispensable requirements of public safety.
The United States and Israeli policy on targeted killing of terrorists will have to reflect a delicate balance. Most important, in any such calculation, will be the protection of civilian populations from jihadist terror-inflicted harms. In those circumstances where harms would involve unconventional weapons of any sort—chemical, biological or nuclear—the legal propriety of targeting jihadists could be patently obvious and lie “beyond any reasonable doubt.”
For both Washington and Jerusalem, legal assessments of targeted killing ought never to be undertaken apart from operational expectations. This means that before any “extraordinary remedies” are applied, these measures would be not just legally correct but tactically gainful. Looking ahead, there could be no more important calculations.