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Assassinating terrorist leaders: A matter of international law

By Louis René Beres


Osama bin Laden was assassinated by U.S. special forces on May 1, 2011. Although media emphasis thus far has been focused almost entirely on the pertinent operational and political issues surrounding this “high value” killing, there are also important jurisprudential aspects to the case. These aspects require similar attention. Whether or not killing Osama was a genuinely purposeful assassination from a strategic perspective, a question that will be debated for years to come, we should now also inquire:  Was it legal?

Assassination is ordinarily a crime under international law. Still, in certain residual circumstances, the targeted killing of principal terrorist leaders can be defended as a fully permissible example of  law-enforcement. In the best of all possible worlds, there would never be any need for such decentralized or “vigilante” expressions of international justice, but – we don’t yet live in such a world. Rather, enduring in our present and still anarchic global legal order, as President Barack Obama correctly understood, the only real alternative to precise self-defense actions against terrorists is apt to be a worsening global instability, and also escalating terrorist violence against the innocent.

Almost by definition, the idea of assassination as remediation seems an oxymoron. At a minimum, this idea seemingly precludes all normal due processes of law. Yet, since the current state system’s inception in the seventeenth century, following the Thirty Years’ War and the resultant Peace of Westphalia (1648), international relations have not been governed by the same civil protections as individual states. In this world legal system, which lacks effective supra-national authority, Al Qaeda leader bin Laden was indisputably responsible for the mass killings of many noncombatant men, women and children. Had he not been assassinated by the United States, his egregious crimes would almost certainly have gone entirely unpunished.

The indiscriminacy of Al Qaeda operations under bin Laden was never the result of inadvertence. It was, instead, the intentional outcome of profoundly murderous principles that lay deeply embedded in the leader’s view of Jihad. For bin Laden, there could never be any meaningful distinction between civilians and non-civilians, innocents and non-innocents. For bin Laden, all that mattered was the distinction between Muslims and “unbelievers.”

As for the lives of unbelievers, it was all very simple.  These lives had no value. They had no sanctity.

Every government has the right and obligation to protect its own citizens. In certain circumstances, this may even extend to assassination. The point has long been understood in Washington, where every president in recent memory has given nodding or more direct approval to “high value” assassination operations. Of course,  lower-value or more tactical assassination efforts in Iraq and Afghanistan have become a very regular feature of U.S. special operations.

There are some points of legal comparison with the recent NATO strike that killed Moammar Gadhafi’s second-youngest son, and his three grandchildren. While this was a thinly-disguised assassination attempt that went awry, the target, although certainly a supporter of his own brand of terrorists, had effectively been immunized from any deliberate NATO harms by the U.N. Security Council’s  limited definition of humanitarian intervention.

It is generally true that assassination is a crime under international law. Yet, in our decentralized system of world law, self-help by individual states is often necessary, and the only alternative to suffering terrorist crimes. In the absence of particular assassinations, terrorists could continue to plan havoc against defenseless civilians in America and elsewhere, and could do so with impunity. To be sure, they would be generally immune to the more orthodox legal expectations of extradition and prosecution. This is not to suggest that assassination will always “work,” but only that disallowing such killing out of hand could never be gainful.

Assassinating bin Laden was consistent with the ancient legal principle of Nullum crimen sine poena, “No crime without a punishment.” Earlier, this core principle had been cited as a rationale for both the Tokyo and Nuremberg war crime tribunals, and was subsequently incorporated into binding customary international law. As to the foreign venue of the assassination, President Obama can find adequate legal support in certain relevant bilateral agreements with Pakistan, and also in pertinent provisions of the 1974 General Assembly Definition of Aggression. Although extra-territorial jurisdiction in any such matters would normally be unlawful, there are critical exceptions when a particular country (here, Pakistan) more or less “allows” its territory to be used as a base of operation for future terrorist crimes.

By the codified and customary standards of contemporary international law, 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.”  That bin Laden’s terror-crimes were plainly directed at the United States in particular removes any doubts about the geo-strategic reasonableness of America’s primary jurisdiction.

Limited support for assassination can be found in the classical writings of Aristotle, Plutarch and Cicero, and even in American history.  Should the community of nations ever reject this right altogether, it would have to recognize, as a corollary, that such rejection could be at the expense of innocent human life. The existing law of nations must, at least on occasion, continue to rely on even the most objectionable forms of self-defense.

International law is not a suicide pact. Assassination, always subject to the applicable legal rules of discrimination, proportionality and military necessity (it is vital that assassinations always seek to avoid collateral casualties) may sometimes be the least injurious form of defense and punishment.  Wherever additional terrorist crimes are still being planned, as was certainly the case with Osama bin Laden, the permissibility of assassination may be far greater.

In a better world, assassination could have no defensible place as counterterrorism. But we do not yet live in the best of all possible worlds, and the obviously negative aspects of assassination should never be evaluated apart from the foreseeable costs of all other options.  Such aspects should always be compared to what would be expected of these alternative choices.

Assassination, even of a terrorist mastermind like Osama bin Laden, will almost always elicit some indignation, ironically, even by those who would likely find full-scale warfare appropriate.  Yet, the civilizational promise of universal reasonableness is unrealized, and imperiled states, including our own, must inevitably confront stark choices between employing assassination in limited circumstances, or renouncing such tactics at the expense of  justice and security.  In facing such choices, these countries, including the United States, will always discover that viable alternatives to the assassination option also include large-scale violence, and that these alternatives may ultimately exact a substantially larger long-term toll in human life and suffering.

Louis René Beres was educated at Princeton (Ph.D., 1971) and is currently Professor of International Law at Purdue University. The author of ten major books and several hundred scholarly articles on world affairs, his columns appear in many major American and European newspapers and magazines.

For further reading, we suggest the biography Osama bin Laden by Michael Scheuer, former chief of the CIA’s bin Laden unit.

Recent Comments

  1. […] The killing of bin Laden in Abbottabad is a major psychological blow to al Qaeda, who lost a charismatic leader, viewed by both his supporters and his enemies as the true symbol of global terrorism and militancy. For many around the world it is a victory in the war against extremist violence which has resulted in the deaths of thousands of innocent people. […]

  2. A. Benway

    The OBL hit does not stand alone, but as part of an ongoing official policy of murder by various means and over a long period. With an open and public policy of murder being bragged about and the hit-men being given medals for especially fine rub-out jobs, some might say that the author is being somewhat disingenuous. A few might even go so far as to opine that by this policy, as seen in the over-all sense, the Anglo-American junta has repudiated the Peace of Westphalia and thus brought the States, the World, to the status quo ante ie 1647, wherein the default international condition was war.

  3. N Coghlan

    This article is deeply flawed in two respects. First, it is circular: it says the prohibition against assassination is not absolute but rather has justification in ‘residual circumstances’. Yet the rest of the article makes very clear this is not the case: it is arguing that there *should* be such a residual exception, for reasons such as necessity, *not* that such a residual power is already recognised. If the author wishes to argue for this, that is fine, but it is dishonest to portray this as a settled and accepted conclusion.

    Second, and more fundamentally, its entire argument hangs on the false premise that the only way to punish OBL was assassination. Yet this was not, according to American authorities, the intention of the operation: it was to kidnap him to have him face justice by trial. Former General McChrystal’s speech to the Cambridge Union, available online, underlines this: he says whilst he was not personally involved, the murder of anyone in cold blood is illegal under international law, so their orders must have been to arrest him if possible. Whether the US really believed this is immaterial: the pretence of a legitimate operation to arrest him completely undermines this suggestion that assassination was the only way to bring him to justice.

    This article approaches the Alan Dershowitz level of respected academics twisting and torturing the clear meaning of international law to serve transparent apologist agendas.

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