Over the weekend, The Washington Post reported on a joint U.S.-Israeli operation that killed Imad Mughniyah—Hezbollah’s reported chief of international operations—on the streets of Damascus in 2008. The account raises questions about whether the killing violated international law, and central to the Post’s story is the assessment that these actions “pushed American legal boundaries.”

But which boundaries exactly and how so?

The international legal issues at stake include:

  • When a state may use force in another country.
  • When a state may use force in self-defense.
  • When a state may intentionally kill an individual.
  • When a state may use specific methods to kill an individual.

(Regular readers of this site will note that these are the same kinds of issues that arise in debates about present-day drone strikes.)

Coverage of and commentary about U.S. killings abroad can often blur together these distinct legal questions, making it difficult for readers to understand which legal frameworks are being applied, and the legal relevance of particular facts. From the Post piece, and the quotes of anonymous officials, it is not clear which international law theory the U.S. relied on to justify its killing Mughniyah.

We are also concerned by the Post’s presentation of a separate legal issue–the prohibition against perfidy under the laws of war. The Post’s description may mislead readers about the definition of this important area of law (we deal with this in Part II below).

I. Legality of killing Imad Mughniyah

So which international legal rules might the Bush administration have claimed justified the killing of Mughniyah and precluded this action from being considered an unlawful extrajudicial execution or “assassination”? And what are the weaknesses or strengths of these legal arguments?

[As an aside: we do not analyze the domestic legal basis for the operation or domestic legal constraints that might apply. That said, whether international law permitted killing Mughniyah would presumably play an important role in such analyses (e.g., the 12333 assassination ban).]

There are two types of international law claims made (or alluded to) by the anonymous officials quoted in the Post story:

Option A: Self-defense outside of armed conflict

The Administration might have claimed that a nation’s right of self-defense permitted the use of force to target Mughniyah. The U.S. argument would be that Mughniyah was directly involved in armed attacks, and even if the United States was not in an armed conflict with Hezbollah, Mughniyah posed a “continuing and imminent threat,” and thus could be killed.

There are two variants of the self-defense option that may have applied in this case.

Variant A-1: The Administration might have claimed that the United States was exercising the right of self-defense because of Mughniyah’s attacks on and threat to U.S. persons.

Variant A-2: The Administration might have claimed that Israel had the right of self-defense to take such actions and the United States was engaged in the collective self-defense of Israel.

These arguments involve numerous complex and contentious elements. For example, the U.S. view that it can use force to respond to “continuing and imminent” threats (rather than an actual or immediately-pending armed attack) is an outlier internationally, and the subject of frequent criticism.

Moreover, the United States’ acting in self-defense would presumably not be a sufficient condition for assessing the legality of this strike. Self-defense may answer the question “when can the state use force,” but it does not answer the question of when and which individuals can be killed. Many international lawyers would say that if there was no armed conflict, and the U.S. was relying on self-defense only, the government would additionally need to comply with the rules for the use of force set out in human rights law. These rules are restrictive – permitting intentional lethal force only when strictly necessary to save life – and the facts of Mughniyah’s killing as outlined in the Post article raise concerns about a violation of these rules. The application of human rights law would also require a more searching inquiry about why the American and Israeli forces were not able to apprehend rather than kill Mughniyah given their close surveillance of him over several months.

[We should note that a separate legal question involves the legality of taking these actions inside another state’s territory (Syria) without its consent.]

Option B: A killing in ongoing armed conflict

The Administration might have claimed that Mughniyah was a lawful military target in an ongoing armed conflict. But which armed conflict?

Version B-1: United States vs. Hezbollah
Version B-2: United States vs. Iraqi armed groups (with Hezbollah/Mughniyah assisting the latter)
Version B-3: Israel vs. Hezbollah (with U.S. assisting Israel)
Version B-4: Israel vs. Syria (with U.S. assisting Israel)

Under any of these variants of an ongoing armed conflict, the United States could be lawfully involved in killing Mughniyah if he was a member of an organized armed group that was party to the conflict or because he was “directly participating in the hostilities.” Notably, in the situation of an armed conflict, the United States does not need to establish that an enemy fighter is an “imminent” threat.

So which legal claims were at work?

Under international law, the administration would presumably first need to satisfy the rules of self-defense (that it can resort to use of force against a threat) and then either human rights law (outside of armed conflict) or the rules of war (in an armed conflict) would determine the legality of the targeted killing of Mughniyah.

What do the Post’s anonymous government officials tell us about the potential legal justification for participating in the killing? Not nearly enough. The story suggests that either Option A-1 (self-defense outside of an ongoing armed conflict) or Option B-2 (killing in an ongoing armed conflict) might be at work. As an example of the latter, the Post states: “Former U.S. officials … asserted that Mughniyah, although based in Syria, was directly connected to the arming and training of Shiite militias in Iraq that were targeting U.S. forces.” Also overlooked is Option B-3 (assisting Israel in killing Mughniyah). An important thread in the set of events is Israel’s potentially direct and independent interest in targeting Mughniyah as part of an ongoing armed conflict between Israel and Hezbollah.

These distinctions are important. Each legal claim has a different degree of strength, and different facts are relevant to their determination. Option B (killing a suspected head of military operations in an armed conflict), for instance, is on much stronger legal footing and less controversial than Option A-1 (use of force outside of armed conflict against a “continuing and imminent” threat). And Option B-2 is potentially compelling.

Option B-3 might be the most important variant because it could simplify the legal challenge. In that case, the lethal action would only have to satisfy the relaxed standards of the laws of war in armed conflict, and the U.S. might be able to assist Israel if the action satisfied those standards. This option would also render seemingly significant statements in the Post’s story legally irrelevant such as “Mughniyah was targeted in a country where the United States was not at war.” The key would be where Israel was at war.  Notably, many of the facts in the Post point in the direction of Option B-3.

The entangling of Option A (self-defense rules) and Option B (targeting in armed conflict rules) has also been seen in Obama administration use of force justifications (see the Justice Department’s White Paper, for a good example), and the writing of some commentators. Consider, for example, Jack Goldsmith’s explication of the Post story at Lawfare. His mixture of the two legal regimes (see this page) makes it difficult to understand which legal rules justified the killing, both in Goldsmith’s interpretation and in the source he cites.

Keeping these legal domains distinct is critical to understanding whether international law permitted the Mughniyah operation and why the decision to kill him might, or might not, have been an unlawful targeted killing or assassination.

II. Method and means of killing Imad Mughniyah

Assuming Mughniyah was a lawful target in an armed conflict, was the method of killing him by a car bomb an unlawful act of perfidy?  Perfidy is a serious and well-established international law prohibition and, as a form of treachery, it is a war crime under the Rome Statute. Yet the Post gives readers the wrong impression about the perfidy prohibition.

The Post reports:

[H]e was killed in a car bombing, a technique that some legal scholars see as a violation of international laws that proscribe “killing by perfidy” — using treacherous means to kill or wound an enemy.

“It is a killing method used by terrorists and gangsters,” said Mary Ellen O’Connell, a professor of international law at the University of Notre Dame. “It violates one of the oldest battlefield rules.”

Killing individuals with car bombs is certainly a technique more associated, in the minds of many, with terrorists than an official act of a government. But is it perfidy? Perfidy is defined as “acts inviting the confidence of an adversary to lead him to believe that he is entitled to, or is obliged to accord, protection under the rules of international law applicable in armed conflict.”  As the ICRC straightforwardly explains, “The essence of perfidy is thus the invitation to obtain and then breach the adversary’s confidence, i.e., an abuse of good faith.”  An example would be where a combatant pretended to be injured as a way to lure an enemy combatant close under the false confidence that he would not attack, and then killing the enemy. Pretending to surrender and then attacking would be another clear example. (See Marty Lederman’s post for further helpful analysis of the law on perfidy.)

It is difficult to see how the circumstances of the killing of Mughniyah, either because of its surprise nature, or because of the specific method of the car bomb, meets this definition or is analogous to the types of acts commonly considered perfidious.

How was Mughniyah lulled into a false sense that he was lawfully protected? As Kevin Jon Heller observes as well over at Opinio Juris, the use of the car bomb simply did not do this. (See also this exchange on Twitter that the two of us had with Kevin Jon Heller and Mary Ellen O’Connell).

Perfidy is not directed at banning certain kinds of weapons. The ban on perfidy exists to protect the rules of warfare from abuse by combatants who would take advantage of them to kill enemies. It aims to deter actors from taking advantage of and manipulating the protections of the laws of war. What rationale or distinction would ban car bombs, but not setting an IED down the road, using a sniper, or launching a missile from above?

Finally, by way of comparison, consider Protocol II to the 1980 CCW Convention (Israel and the United States are both parties). That agreement regulates devices like the bomb used in the Mughniyah operation (Article 2(5)), and it prohibits hiding them in a list of objects such as children’s toys and ambulances (Article 7). Ordinary vehicles are not on the list, nor can they be “read in” by analogy with any of the listed objects.