Self-Defense and Strategic Direction in the Skies Over Syria


In the month of June, the United States, though ostensibly not at war against the Syrian regime or its allies, took at least three actions in self-defense that appeared to escalate tensions with those actors. The Air Force first downed an Iranian Shahed-129 drone, followed by the Navy shooting down a manned Syrian SU-22 Fitter. The next day, the Air Force shot down a second Shahed-129. While the weight of the U.S. military effort in Syria and Iraq is directed toward the defeat of the Islamic State (ISIL), in these cases force was directed at the Syrian government and its allied militias. The incidents sparked some debate about how self-defense can affect strategic direction and whether tactics are driving strategy in Syria. The use of force against targets not related to ISIL risked escalation with the Assad regime and its allies, an outcome that would alter the scope of American involvement in the Syrian civil war.

The potential for the three episodes to broaden the objectives of the current war reignited a conversation in Washington about whether military escalation in Syria would serve U.S. interests in the Middle East. The debate about “rightsizing” the U.S. military footprint in Syria has raged for years. Proponents of escalation argue in favor of deepening involvement in the civil conflict, using force to overthrow the Syrian regime or arming proxies to compel Bashar al-Assad to step down as part of a negotiated settlement. On the other side, opponents of escalation argue that the cost of challenging Iran in Syria outweighs any benefit, and that the current strategy of working with and through the Syrian Democratic Forces (SDF) is effectively forcing ISIL from territory it controls.

The polarized debate reflects a broader question about the nature of the war Washington intends to fight. If the policy objective is ambiguous and the United States strives to maintain a light footprint, a particular challenge emerges: a temptation on the part of policymakers to micro-manage tactical decisions, often in ways that are incongruent with the speed of combat and the complexity of multi-sided civil conflict. The interplay between the policy world and tactical decisions has considerable impact on how effectively the military can fight wars. This is particularly true in the Syrian case, where many of the actors don’t wear uniforms, information is imperfect, and different actors allied with different outside powers operate within mortar range of one another along porous front lines.

Policy Assumptions and the Reality of Combat

There is a common misconception, even within the military, that war is simply a targeting exercise controlled by an omniscient operations center a thousand miles away. Things like precision weapons and satellite-based intelligence are supposed to enable decisive, surgical warfare in which only the bad guys die, local hearts and minds are “won,” and success is easily measured in PowerPoint slides. Unfortunately, war is much more complicated than that, because it happens in a world of coevolving actors, incomplete information, and, at times, quixotic policy assumptions on all sides. Bridging the gap between policy assumptions and the reality of combat is something statesmen and military leaders have struggled with for ages.

It’s important to distinguish policy from strategy and tactics. Hew Strachan defined strategy as applying military means to a political end. Strategy is essentially the intellectual architecture for using military force against an armed opponent to serve political ends. Tactics are the physical actions of strategy – actions that exist in a world where killing, death and destruction are real and opposing actors are constantly resisting through their own policy objectives, strategy, and tactical adaptation. Policy, on the other hand, is a statement of government intent within a set cost.

Commanders and policymakers attempt to align tactics to policy through the rules of engagement, which govern the who, what, where of physical actions. Since tactics are primarily about winning and surviving, there is a natural tension between military effectiveness and policy factors such as controlling escalation or avoiding negative domestic reactions. In turn, this means policymakers may be tempted to micromanage force application to fit the policy factors.

However, combining unrealistic policy goals with micromanagement is a recipe for disaster, a point tragically illustrated by the bombing of the Marine Barracks in Lebanon in 1983, where Marines were restricted from taking appropriate self-defense measures for fear they would appear aggressive or have an incident with the local population. Ultimately, US forces left without realizing any policy goals. In sharp contrast, historically savvy and combat experienced commanders in Operation Inherent Resolve have emphasized the imperative of self-defense and hewing to militarily feasible objectives, such as the defeat of ISIL.


The United States can only lawfully use violence against an officially “declared hostile force,” a legal authority currently drawn from the Authorization to Use Military Force (AUMF) and/or presidential powers, depending on who you ask. Actors who have not been officially declared hostile may only be engaged under self-defense, an inherent right reserved by the standing rules of engagement. Self-defense against such peripheral actors follows a “hostile act” or demonstration of “hostile intent.” A hostile act is relatively easy to discern – but only after the act takes place. Given that U.S. forces are concerned with defense against hostile acts, this can pose a problem. “Hostile intent,” however, is significantly harder to discern, particularly in a time-compressed environment such as aerial combat where an accurate assessment must be made in minutes or even seconds.

In the case of the first Shahed-129 shoot-down, determining hostile intent was complicated by the fact that the Iranian drone was operating just outside the established de-confliction zone, the high tensions between the various actors on the ground, and the very close proximity of Russian fighters to the pro-regime drone. This combination created something of a Mexican standoff, in which each actor has a gun pointed at the other, and in this case, escalation with a peripheral actor was only the push of a button away.

However, when the Shahed-129 used force against coalition troops, it made an obvious case for the necessity of self-defense despite the aerial brinkmanship on display. With the price of both inaction and escalation high, the situation required a deliberate, calculated, and timely response – a decision that must continue to rest with the aircrew at the scene, supported by a command and control center. The combined air operations center (CAOC) does communicate with Russia in real time for deconfliction, but these conversations are understandably asynchronous to the speed of tactical combat – an important point emphasized by Lt. Gen. Jeffrey Harrigian, the Combined Forces Air Component Commander.

The downing of both Shahed-129s illustrated the extreme complexities of the battlefield, where U.S. forces routinely operate in close proximity to Syrian regime forces, Iranian militias, Russian elements, or other factions with undetermined or maligned interests. “Pro-regime” forces or “militias” can mean any number of possibilities for the coalition, and assumptions can be fatal. The staggered front line separating U.S.-backed irregular forces requires aircrews to discern the intent of the aircraft or vehicles approaching the front line, something that is rarely clear-cut.

Deconfliction Zones and the Limits of Escalation

The downing of the two Iranian drones and the Syrian aircraft in quick succession, and the subsequent agreement on deconfliction zones in eastern Syria, raise two broader policy questions: What does the United States intend to do to protect partner forces it has relied on, up until this point, to fight the Islamic State? And how do these questions intersect with the tactical perspective, wherein aircrew and personnel will be asked to make rapid decisions to protect U.S. or partnered forces?

Secretary of Defense Jim Mattis made clear that American-supported forces are going to continue to move down the Euphrates River towards the border with Iraq. At the same time, the regime and Iranian-backed forces are slowly pushing towards Deir al-Zour from Palmayra and from positions south of Tabqa. This will bring U.S. and regime allied forces into closer proximity, making it all but inevitable that questions of rules of engagement and self-defense will arise again.

Thus far, the United States has managed to de-escalate such situations. After the downing of the SU-22 near Tabqa, for example, The Washington Post’s David Ignatius reported that the two sides agreed to a 130-kilometer deconfliction line from Tabqa to the town of Karama. The arrangement is similar to the 55-kilometer deconfliction zone around a military garrison near Tanf, a border town on the highway connecting Damascus with Baghdad. The establishment of these two zones raises difficult questions: Does the United States intend to defend these areas from regime and regime-allied attack, and, if so, for how long?

In the wake of the SU-22 shootdown, CENTCOM took a step towards answering the question, indicating in a press release that it would “not hesitate to defend Coalition or partner forces from any threat.” The statement suggests that the U.S. military is now committed to protecting the Syrian Democratic Forces — even if they are attacked by regime or regime-affiliated forces with whom the United States is not at war.

The result is that U.S. military forces will have to continue determining whether actions by local actors on the ground who may seek to test deconfliction boundaries are “hostile” and should be met with self-defense strikes. In the absence of changes to the legal authorities, U.S. policymakers will need to think through how the declaration of deconfliction zones may inadvertently lead to escalation when those zones are questioned, and to ensure that these zones contribute to the end goal of defeating ISIL. The challenge is that the incentives to try and control the risk of escalation are still present. Yet, the battle space has grown more complicated as regime and regime-allied forces have moved into closer proximity to U.S. actors. The danger, then, is that policy objectives — and, thus, the rules of engagement — will not truly reflect the situation on the ground or in the skies above it.

Policy and Tactics

In the skies above Syria, not all adversary aircraft are created equal. For the aircrews in the anti-ISIL coalition, escalation with a global power like Russia is far riskier than with a failed state like Syria, further complicating what is already a very difficult decision-making process. Still, the actions taken in the past few months underscore how policymakers must keep up with the changing nature of the Syrian battlespace and the convergence of multiple actors in the eastern Syrian desert. Looking at a map, the two sides may converge in Deir al-Zour province, an ISIL stronghold on the southern side of the Euphrates River. The hostile forces, in turn, will both be fighting the same enemy, ISIL, albeit on opposing sides and for different reasons. For Washington’s part, unless legislators change the legal restraints on the use of force, U.S. actions will remain focused on Islamic State, with any peripheral engagements falling under the self-defense rules of engagement.

As difficult as it may be to apply these rules to a ground situation, the challenge faced by aircrews is compounded by the pace of air combat. However, if an engagement is provoked, both sides may be driven to make split-second decisions. These decisions cannot be micro-managed, even though the repercussions of escalation may impact the broader policy objectives that the use of force is intended to help realize.

The risk of escalation is inherent to the current mission and stems from the United States being one party to a multi-sided civil conflict, in which the majority of the actors are hostile to American interests in the region. The role of policymakers, therefore, isn’t to micro-manage tactical decisions, but to assess whether their objectives are based on realistic assumptions. Making good policy depends on weighing these obvious risks before deciding to use force in the first place.

The political incentive to manage the escalation risk is clear, but the enemy — or at least battle space co-habitant — also gets a vote in the matter. In Syria, the conflict is so complicated, and the viable political choices so untenable, that it is difficult for America to articulate clear objectives beyond the defeat of ISIL. Meanwhile, the speed of combat is a constant, placing it perpetually in tension with policy objectives. It is critical for tactical actions to be based on sound strategic objectives, rather than driving debates about what those objectives should be.


Ryan Fishel is a F-15E Weapons Systems Officer with 400+ combat hours in Operation Inherent Resolve. Aaron Stein is resident senior fellow at the Atlantic Council’s Rafik Hariri Center for the Middle East.The views expressed in this article are the authors’ alone, and do not reflect the official position of the U.S. government, the Department of Defense, or the U.S. Air Force.

Image: Air Force photo by Staff Sgt. Sandra Welch