This week American-led airstrikes deterred the advance of a convoy carrying a group of ISIS fighters and civilians as it traveled from Lebanon to an ISIS safe-haven in Syria. The convoy reportedly consisted of a mix of buses and ambulances carrying 26 wounded fighters, 308 armed fighters, and 331 civilians.

For the time being, it does not appear that the civilian-laden convoy was the actual object of attack. Not all the details are public, but according to Reuters the strike deterred the convoy by cratering a road and hitting ISIS members who were on their way to meet the convoy. This is consistent with a Coalition statement claiming that it had not struck the convoy but struck “individual vehicles and fighters that were clearly identified as ISIS.”

While airstrikes involving civilians often prompt questions about their legality under the laws of war, known as international humanitarian law (IHL), at this moment, this strike also raises a set of important legal questions surrounding the unique events that occurred prior to the strike on the Lebanese side of the border.

In Lebanon last week two separate anti-ISIS operations on the border with Syria—one led by Lebanese forces and another run by Syrian and Iranian-backed Hezbollah forces—resulted in the capitulation of hundreds of ISIS fighters. Immediately after this, a bargain was struck amongst these groups that led to a ceasefire and a prisoner swap. Under its terms, hundreds of ISIS fighters and civilians (presumably their family members) were loaded onto buses, some labeled with the tour company name “Happy Journeys,” and were allowed safe passage into Syria. This was in exchange for the bodies of an Iranian soldier, two other fighters that ISIS had killed, the surrender of a Hezbollah fighter, and information about the fate of Lebanese soldiers ISIS had captured back in 2014.  The convoy departed on Monday. On Tuesday, it arrived in Homs, Syria, where the people were transferred into ISIS buses and ambulances. Wednesday was the day of the U.S-led strike.

The fact that ISIS fighters surrendered in Lebanon and were granted free passage to Syria raises three distinct legal issues that are important for ensuring that in the midst of horrendous acts of violence states hold war criminals responsible for their crimes and that warring parties don’t needlessly kill civilians, wounded soldiers, or people who have put down their arms regardless of their past affiliation with ISIS. 

Were anti-ISIS forces in Lebanon allowed to release these fighters?

International law requires states to investigate and, if appropriate, prosecute people in their jurisdiction suspected of engaging in particularly egregious acts, such as war crimes. Although the Geneva Conventions spell out the requirement for states to do so most clearly in the context of wars between states, known as international armed conflicts, there is sufficient state practice to establish this obligation as a rule of customary international law in what’s known as known as non-international armed conflict, that is, wars involving states fighting non-state actors or non-state actors fighting one another, much like we see in Syria. If any of those surrendered ISIS fighters were suspected of committing war crimes and other egregious acts and hadn’t then been investigated by local authorities, they shouldn’t have been released under the terms of international law.

If, however, any of the fighters weren’t suspected of such acts, then Lebanon’s obligation under international law to prosecute might not be so clear.  In fact, in an attempt to prevent the human rights abuses that too often accompany victor’s justice, and also to allow authorities the flexibility to deal with situations of post-conflict reconciliation and transition, IHL encourages authorities in power at the end of a non-international armed conflict to grant amnesty to those who participated in the conflict. This is, unfortunately, a part of IHL that is too often overshadowed by ever-expanding international anti-terrorism law and anti-terrorism law enthusiasts who insist that no act of terrorism—not matter how broadly defined, insignificant, or disadvantageous prosecutions are to domestic politics—should go unpunished.

What was the convoy’s legal status under IHL?

Given that Hezbollah, Lebanese, and Syrian forces all agreed to grant the convoy safe passage into Syrian, the convoy—and all its various parts—would appear to have been legally protected from attack by the parties to the agreement, provided of course that the ISIS fighters did not re-engage in hostilities. Quite simply, having laid down their arms (whether actually or metaphorically), ISIS fighters—at least in the eyes of Hezbollah, Lebanese, and Syrian forces—turned into ex-fighters. With family members (civilians) and wounded ISIS fighters (classified as hors de combat) being the only other people reported to be in the convoy, the convoy had full legal protections from attack by Hezbollah, Lebanese, and Syrian forces.

But what’s true in the eyes of some isn’t always true in the eyes of others. In its statement justifying its attack, the coalition noted that it was not party to the agreement and described the convoy as a plan to nefariously relocate “terrorists from one place to another for someone else to deal with.” The coalition didn’t appear to give credibility to any notion that the ISIS fighters had permanently or even temporarily left the fight. Quite the opposite, according to the New York Times:

“We’ve seen ISIS use protective sites like hospitals and mosques, seen them drive in ambulances,” Colonel Ryan said. “So if we do identify and find ISIS fighters who have weapons — we can discriminate between civilians and ISIS fighters — we will strike when we can. If we are able to do so, we will.”

Add to this the factor that Hezbollah and the Lebanese army likely allowed the convoy safe passage into Syria for their own short-terms goals, and they may not have been very fussed about what the ISIS fighters did once they arrived at their far-off destination.

But if the Coalition ever in fact targets what it is defining as the “ISIS fighters” in the convoy, the lawfulness of such an attack will need to turn on the quality of information it has, and seeks to obtain, about the convoy at the time of an attack In other words, this decision can’t be solely based on general assumptions. For example, it would be important for the Coalition to seek out prior to any attack whether the ceasefire agreement committed the fighters not to take up arms ever again or, alternatively, if the fighters have committed themselves to re-engaging in hostilities the moment they reach their final destination; just as easily as it is for a fighter to turn into an ex-fighter, the reverse is also true. Perhaps the fighters in the convoy simply don’t know what they’ll do once they reached their destination.

Whatever the case, seeking out this type of information is particularly important for the Coalition to ensure its meeting its obligations to take all feasible precautionary measures against harming civilians and fighters who are no longer party to a conflict.  If the ISIS fighters have permanently disengaged or if their intentions are unclear, it’s hard to see how IHL could justify a strike against the convoy. If, on the other hand, the convoy was just transporting them to their next battle-stage, then IHL would not protect the abled bodied fighters in the convoy from being regarded at potentially lawful target.

But, of course, even if the Coalition did have adequate information to justify such an attack, a host of legal issues would have to be addressed, such as carefully distinguishing between civilians and lawfully targets, taking appropriate precautionary measures to avoid civilian harm, ensuring that the strike meets the rules of proportionality, and respecting the protections that IHL grants to wounded fighters and ambulances.

Are “mixed” convoys lawful?

IHL requires warring parties to take precautions to protect civilians under their control against the effects of attack. For example, a state should avoid placing tanks in the middle of a civilian market. The purpose of this rule it to avoid creating a situation where the enemy launches an attack that could result in heavy civilian casualties.

This rule may not seem immediately relevant to the convoy since Lebanese, Hezbollah, and Syrian forces granted it safe passage. A few concerns arise nonetheless: First, it’s a problem if the ISIS fighters or ex-fighters purposefully placed themselves in a mixed convoy as a way of using the civilians and wounded fighters as human shields to ensure that they didn’t come under attack, be it from Lebanese, Hezbollah, Syrian, or Coalition forces.  This, of course, doesn’t wash away the responsibilities of an attacking force to nonetheless apply the rules of distinction, precaution, and proportionality noted above.

Additionally, it’s worth asking whether Lebanese, Hezbollah, and Syrian forces thought the Coalition might strike the convoy. If they thought it might, and depending on the degree of control those forces had over the convoy at its point of departure or during its journey, it would have been important for them to use any authority or influence they had to, for example, separate different categories of people from each other and to space out the distances between the vehicles as the convoy approached the border. The reporting I’ve seen isn’t clear on these types of details. Either way, these are the sorts of measures that could foreseeable prevent the use of human shield and mitigate the risk of civilian harm in anticipation that an attack might occur.   

Image: US Defense Dept.