“We can save many, many, many lives by making a deal with Russia having to do with Syria, and then ultimately getting Syria solved.”

—U.S. President Donald Trump

“Russia [has] clearly been and has been for quite a long time a country which defines in part its interests as thwarting the United States, and . . . it’s very hard to align yourself with them, as we have done in the past. . . . I didn’t want the United States to be associated, either politically or morally, with what the Russians were doing [in Syria]. And of course, they were intent upon trapping us, or beguiling us into what they called cooperating with them, and I was against cooperation.”

Former U.S. secretary of defense Ash Carter


Since the beginning of Russia’s intervention in September 2015, the war in Syria has been a major potential flashpoint in the increasingly adversarial U.S.-Russian relationship. To mitigate the risk, senior U.S. defense officials have prioritized practical mechanisms to deconflict U.S.-Russian military activities and to limit the threat of inadvertent escalation or confrontation. Key regional players like Israel and Turkey have created similar deconfliction procedures. Nevertheless, Syria’s crowded battlefield has witnessed a number of deadly incidents and near-misses, including the inadvertent downing of a Russian Il-20 military intelligence collection aircraft by the Syrian military in September 2018 and a brazen assault by Russian private military contractors on an outpost manned by U.S. special operations forces in February 2018.

At various junctures, senior U.S. officials have entertained establishing more ambitious forms of U.S.-Russian cooperation in Syria. Under former U.S. president Barack Obama, discussions centered on possible intelligence sharing and joint targeting of terrorist groups. Trump’s inner circle came into office convinced that cooperation with Moscow in the fight against the self-proclaimed Islamic State was a key element of the president’s vision for a vastly improved relationship with Russia, as well as a potential step toward luring the Russians away from their tactical alliance with Iran. Russian President Vladimir Putin has kept more intimate forms of cooperation on the table both for propaganda purposes and as a source of leverage over the United States. Putin himself made the issue a centerpiece of the tumultuous Helsinki summit in July 2018.

This paper explores the evolution of the deconfliction effort over the past three years and why discussions about deeper U.S.-Russia military-to-military cooperation in Syria failed to produce meaningful results. It draws on interviews with current and former U.S. officials as well as open source material in English and Russian to answer three core questions: Is deconfliction a sufficient end in itself, given the levels of mistrust that are now pervasive on both sides? Were repeated high-level Russian expressions of interest in cooperation genuine or simply part of a cynical effort to buy time for military efforts to pay off? Was an opportunity missed to forge practical cooperation or did the wide disparity between U.S. and Russian strategic objectives make that impossible?

Andrew S. Weiss
Weiss is the James Family Chair and vice president for studies at the Carnegie Endowment, where he oversees research on Russia and Eurasia.
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A close examination of U.S.-Russian military-to-military ties in Syria also can help shed light on how political leaders and military professionals on both sides were able to maintain productive lines of communication and avoid dangerous situations in the wake of the dramatic breakdown in relations triggered by Russia’s war in Ukraine.

A Highly Adaptive Russian Strategy

There is no question that Russia’s relatively modest outlay of military power in Syria has paid off handsomely, and that the Russian military has largely run the show. The Kremlin managed to save Syrian President Bashar al-Assad’s regime and transform the direction of Syria’s civil war. The operation created significant leverage vis-à-vis the United States and its regional partners, and decisively returned Moscow to the ranks of top-tier players in Middle Eastern power politics. Russia’s intervention was done on the cheap, with only thirty to forty combat aircraft, twenty-odd helicopters, several hundred mercenaries, and no more than 4,000–6,000 ground troops stationed inside Syria at any given time—far less than the vastly superior military capabilities arrayed in other parts of the Middle East by the United States, Israel, Turkey, and other regional players.

Against that backdrop, it is easy to question whether the Kremlin actually hoped that the Syria conflict would serve as a mechanism to refashion its badly damaged relationship with Washington. And while the Russian intervention has not solved all of Syria’s myriad problems (far from it), there is no question that it allowed Putin to address many of Russia’s problems—namely its post-Ukraine political isolation and long-standing desire to force the United States to deal with Moscow largely on its own terms.

The Kremlin’s strategy unfolded along military, diplomatic, and regional lines simultaneously. Russian military planners demonstrated a remarkable capacity for learning and operational flexibility, making frequent adaptations and adjustments along the way. In the words of Israeli military strategist Dmitry (Dima) Adamsky, the Kremlin’s strategy carefully avoided overextension while keeping “political-military confrontations between the parties high enough to sustain the prospects for Moscow’s indispensability but not so high that they lead to a counterproductive escalation endangering its regional interests and assets.” At the same time, the shifting fortunes of Russia’s intervention (for example, a series of military mishaps and setbacks in late 2015 and early 2016) made U.S.-Russian cooperation more desirable at certain junctures. U.S. military deployments inside Syria and a territorial division of labor that put U.S. forces and their allies in the lead east of the Euphrates River also meant that the deck was not always stacked in Russia’s favor.

When things were going well for the Kremlin, Russian officials appeared to relish the role reversal they had engineered vis-à-vis the United States. In private, they told U.S. counterparts that Washington could no longer dictate the terms of Russian involvement as it had done in venues such as the Balkan wars of the 1990s. The Russians capitalized effectively on a close working relationship with the Assad regime and the extensive web of connections forged during their decades-long military and intelligence presence in Syria. At the same time, Russian leverage over the Syrian regime, its Iranian patrons, and other regional players always had certain hard-to-overcome limits. When sticky situations arose—for example, Israel’s ongoing campaign against Iranian military targets and infrastructure inside Syria or the standoff with Turkey over Idlib Province and the northern city of Manbij—the Russians were reluctant to go to the mat.

It was in this context that the Kremlin sought to jump-start U.S.-Russian cooperation, focusing primarily on joint counterterrorism efforts. The outlook for cooperation was never particularly promising, given the two countries’ conflicting strategic objectives in Syria and long-standing tensions between intelligence and military players on both sides. With the Assad regime under intense pressure during 2015 and the first months of 2016, U.S. policy focused primarily on whether the Kremlin could help support efforts to engineer Assad’s removal and to limit Iran’s influence. To Russian ears, such requests betrayed a total lack of seriousness. To U.S. officials, Moscow’s failure to make any headway on these goals—while continuing to pound the moderate Syrian opposition (rather than the Islamic State) with little regard for the safety of noncombatants—persuaded many in Washington that the Kremlin was not sincere about cooperation.

Russian-Iranian joint efforts began to turn the tide of the conflict during 2016 and 2017. Washington and its regional partners soon found themselves in the awkward position of negotiating terms of surrender for the same forces they had supported during earlier phases of the conflict. Against the backdrop of sustained Russian pressure on U.S.-backed Syrian forces, the Pentagon prioritized its counter–Islamic State core mission, Operation Inherent Resolve. As the assault on the Islamic State’s physical assets accelerated, U.S. commanders carefully countered Russian attempts to push the United States out of parts of Syria desired by the Assad regime.

Russia’s knack for getting inside the heads of its adversaries, including the United States, was equally important. Deliberately risky maneuvers in the skies above Syria sent a clear message about the potential downsides of interfering with Russian operations. Likewise, high-profile Russian deployments of advanced surface-to-air missile systems such as the S-300 and S-400 created an anti-access/area denial (A2/AD) envelope within which U.S.-led coalition and Israeli aviation assets were obliged to operate. Curiously, the Russians used these systems largely for signaling purposes and seldom painted other countries’ jets. (While U.S. forces have always had the capability to destroy Russian A2/AD capabilities, there was no appetite for a direct military confrontation on either side.) As widely noted, it didn’t hurt that the operation showcased Russian weaponry for prospective purchasers in the region and enabled useful combat rotations for tens of thousands of Russian personnel.

Deconfliction: An End in Itself?

The first incarnation of the deconfliction mechanism was established following a high-profile meeting between Putin and Obama at the United Nations General Assembly in late September 2015. The atmospherics at the time were colored by Russian diplomatic antics, an intentional lack of consultation about the beginning of its air operations in Syria, and the Pentagon’s determination to avoid any slowdown in its counter–Islamic State campaign. As former U.S. secretary of state John Kerry recounted, “The Russians told us [during the Obama-Putin meeting] they were sending their military into Syria in a typical Russian manner—which is to say, they didn’t tell us at all.” A day later, a three-star Russian general walked into the offices of the U.S. defense attaché in Baghdad and demanded a halt to U.S. air missions over Syria.

Kerry wrote in his memoir that Russian Foreign Minister Sergey Lavrov appeared out of the loop when Kerry asked him to explain press reports about the beginning of Russian bombing raids and troop deployments. In a similar vein, former U.S. defense secretary Ash Carter later asserted publicly that he had been misled by his Russian counterpart, Sergei Shoigu, about the goals of the Russian military operation.

What they did isn’t what they said they were going to do. What they said they were going to do is come in and find ISIL, and help to use their influence to move [Bashar al-Assad] aside and thereby end the civil war in Syria, which has been one of the causes of the whole fertile ground for ISIL. They didn’t do either of those things.

Discussions between the Pentagon and the Russian Defense Ministry quickly produced a memorandum of understanding that covered air safety protocols, the use of specific communication frequencies, and the establishment of a twenty-four-hour, on-the-ground operational communication line. The original agreement was geared toward ensuring that coalition and Russian operations remained separate, that planes did not fly at the same altitude or location, and that airstrikes did not hit “friendlies” of the other party. Still, the term “deconfliction” proved nebulous enough to serve a variety of purposes over time.

Nicole Ng
Nicole Ng was a research assistant in the Russia and Eurasia Program.

From the outset, the Russian side groused that Washington was holding back on more meaningful opportunities for cooperation and intelligence sharing. In mid-October 2015, Putin complained, with trademark sarcasm, that the dialogue between U.S. and Russian officials was largely an exercise in frustration: “We said . . . ‘Give us the targets that you are 100% certain to be terrorists.’ They replied, ‘No, we are not ready to do that.’ So then, we thought about it and asked another question: ‘Then tell us, where shouldn’t we be bombing?’ No response there either.”

The Obama administration’s initial desire to keep any dialogue with the Russian Defense Ministry strictly limited to mid-level officials was soon overridden when Turkey shot down a Russian Su-24 jet near the Turkish-Syrian border in November 2015. In an effort to head off escalation from the Russian side, Chairman of the Joint Chiefs of Staff General Joseph Dunford contacted his Russian counterpart, General Valery Gerasimov, and indicated that the United States would take any necessary action to defend itself. This simple but tough signal of U.S. resolve helped deter any impulsive Russian moves against coalition aircraft in the tense weeks that followed.

Dunford’s early intervention in a dangerous situation and willingness to engage the Russians at a very senior level created a valuable framework for dialogue that continues today. From that point on, professional soldiers, not political appointees, generally took the lead on ensuring that military activities would not create dangers for the other side. The United States, on multiple occasions, laid down firm yet credible redlines for dangerous conduct by Russian forces. It also used the deconfliction channel to manage tricky situations, such as U.S. airstrikes against sites associated with Syrian chemical weapons activities in April 2017 and April 2018. Crucially, both sides agreed to keep the substance of their discussions out of the public eye.

Dunford and Gerasimov did not discuss Syria deconfliction face-to-face until February 2017, when the Trump administration relaxed restrictions on high-level contacts that were imposed after the Russian annexation of Crimea. The Dunford-Gerasimov channel was supplemented by other arrangements, including a twenty-four-hour hotline that connects mid-level U.S. officers at the Combined Air Operations Center (CAOC) in Qatar with their Russian counterparts at Khmeimim Air Base in Syria, and a dialogue at the three-star level between the Joint Staff’s director for strategic plans and policy (currently Lieutenant General David W. Allvin) and his Russian General Staff counterpart. There is also a comparable channel in the theater between the commander of Operation Inherent Resolve and his Russian counterpart at Khmeimim air base. A ground operations element was added in summer 2017 as the Islamic State’s physical caliphate crumbled.

U.S. defense officials are at pains to emphasize that they do not coordinate military activities with Russia. Military cooperation with Russia was explicitly prohibited by provisions of the fiscal year 2015 National Defense Authorization Act (NDAA), which have been renewed annually. (The National Defense Authorization Act was amended for fiscal year 2019 to clarify that the limitation on military cooperation should not be “construed to limit bilateral military-to-military dialogue . . . for the purpose of reducing the risk of conflict.”) Given the NDAA provisions and the overriding need to preserve operations security and freedom of action for U.S. commanders, the United States has instead carefully telegraphed its intentions at times, conveying just enough information to encourage Russian counterparts to limit the risk of inadvertent confrontation or the possibility of Russian personnel being at the wrong place at the wrong time. Although the Russian Defense Ministry has announced the suspension of the deconfliction effort several times during public fits of pique, the line has never actually been shut down.

Still, at moments of extreme danger—most vividly, the February 7, 2018, attack on U.S. special operations forces deployed at a former Conoco plant in Deir Ezzor Province that left hundreds of Russian private military contractors dead or wounded—the deconfliction effort’s limitations have been on display. That the risk of escalation has not been completely eradicated is a reminder that events in Syria are not occurring in a vacuum and are merely one element of a very difficult bilateral relationship.

A series of dangerous incidents involving Russian aircraft in and around Syria are, in many respects, a natural extension of the too-close-for-comfort intercepts and barrel rolls performed by Russian jets over Western military planes and ships along Russia’s increasingly contested frontline with NATO in the Baltic and the Black Sea regions. These in-your-face tactics have helped cement deep reluctance in U.S. policy and military circles about the potential benefits of expanded cooperation with a government that intentionally exploits the threat of military accidents as a political tool and source of leverage. Given the West’s conventional military advantage, Moscow sees these asymmetrical tactics as a valuable tool for pushing adversaries away from strategically important areas and testing whether the West can be intimidated. Making a bad situation even worse are lingering concerns inside the U.S. national security bureaucracy about the situational awareness of Russian regional commanders and the lack of tested crisis communication mechanisms at the political level.

Sharp Internal U.S. Divisions

Moscow’s decision to intervene in Syria, in Kerry’s words, “fundamentally and irretrievably changed” the course of the war and “upped the ante to a degree which we could not match.” Undaunted, Kerry used the next several months to try to coax Moscow and factions on the ground to agree to a cease-fire and a possible road map for a political solution. Even though most of Moscow’s airstrikes during the initial phase of its intervention were confined to non–Islamic State targets, Kerry obtained presidential approval to dangle the prospect of military cooperation as a sweetener for Russian support on the diplomatic track.

Kerry’s efforts were borne in part out of conviction that the 2013 deal on the destruction of Assad’s chemical weapons arsenal had shown that Washington and Moscow could successfully work together on major Syria-related initiatives, largely on U.S. terms. This time around, however, there was no credible threat of force to back up U.S. diplomacy. Indeed, the Pentagon’s leadership was strongly opposed to any military role in Syria beyond Obama’s “ISIL first” strategy (prioritizing the Islamic State’s defeat), which was launched in autumn 2014. Nor was there any meaningful dialogue between military experts about what increased cooperation on Syria might look like. In 2013, multiple rounds of secret talks about Assad’s chemical weapons arsenal had established an important analytical foundation that eventually contributed to the success of the Obama-Putin deal on removing them.

At the same time, it was hard to overlook the extent to which core U.S. and Russian policy objectives in Syria were largely incompatible. For the Russians, the overriding goal was to save the Assad regime, to thwart U.S.-backed regime change efforts, to neutralize radical and terrorist groups, and to preserve Moscow’s sole military foothold in the region. Having ruled out direct military involvement in the civil war, the Obama administration sought to defeat the Islamic State and alleviate the humanitarian impact of the conflict. The only significant potential area of overlap between these two sets of goals was the fight against the Islamic State.

That set the stage for a fateful U.S. policy decision in late 2015. Could the administration work with Moscow on a cease-fire? There was an implicit understanding that such efforts to limit the bloodshed would also include exploration of U.S.-Russian joint targeting of terrorist groups, a prerequisite for Putin’s approval. Before embarking on this initiative, the Obama administration needed to decide whether such cooperation would focus on the Islamic State or groups linked to al-Qaeda, such as al-Nusra.

For some officials at the State Department and National Security Council (NSC), a joint campaign against the Islamic State seemed defensible. The enemy was already clearly defined. U.S. forces were already engaged in the battle against the Islamic State in northeast Syria. The Russians could be helpful in areas that were beyond the reach of the U.S.-led coalition at the time, such as Palmyra and Deir Ezzor. Moreover, it made strategic sense to keep the focal point of Russian operations away from the country’s strategic Western spine, where the moderate opposition was strongest.

Carter and other Pentagon officials were steadfastly opposed to any cooperation in the fight against the Islamic State and insisted on limiting potential cooperation to the fight against al-Nusra. They argued that the coalition didn’t need Russian help, that Russia’s blatant disregard for civilian casualties could potentially blow back on the coalition, and that it was a mistake to put Moscow on an equal footing at the same time Western governments were trying to isolate it. Attempts by Russian Defense Minister Shoigu to engage directly with Carter via telephone were rebuffed, as was a Russian proposal to set up a joint operations center in Jordan. The Pentagon’s arguments carried the day with Obama.

In retrospect, this outcome may have been the worst of both worlds. On the one hand, U.S. hopes that a cease-fire would preserve the stalemate prevailing in other parts of the country while reducing the pressure on Aleppo, at the time a key target for joint Syrian and Russian operations, proved illusory. On the other hand, the decision to focus on possible cooperation against al-Nusra gave the Russians an implicit green light to intensify operations in regions where U.S.-backed Syrian opposition forces were concentrated or held the upper hand. In diplomatic exchanges and in public, the Russians routinely highlighted the comingling of U.S.-backed opposition groups with al-Qaeda-linked fighters as justification for escalated military operations. The Russians demanded that such groups be separated or, at least, properly identified. Both options were largely beyond U.S. capabilities at the time.

The cessation of hostilities began at the end of February 2016. The truce was hampered by a lack of robust enforcement and information-sharing mechanisms about violations. An exception for strikes against al-Nusra (whose fighters were, in fact, frequently co-located with moderate opposition groups) and the Islamic State was quickly exploited by the regime and the Russians. As the level of violence dropped sharply (albeit for only a short-lived period), U.S. and Russian diplomats sought to kick-start the Geneva peace process. By April, the resumption of fighting had overshadowed the diplomatic track, leading to new U.S. gambits aimed at tempering the Assad regime’s gains on the battlefield as well as the humanitarian toll of its siege tactics and use of barrel bombs. By summer 2016, the Kerry team had embarked on a new cease-fire initiative centered on enlisting Russian help to ground Assad’s air force. The sweetener this time was U.S. willingness to set up a joint operations center for intelligence sharing and joint targeting activities. The Kerry team’s ideas sparked considerable controversy inside the Obama administration, and elements of the negotiation were leaked in July 2016.

According to the terms of the deal, Washington and Moscow would share targeting data and coordinate airstrikes if the cease-fire held for a full week. In exchange, Russia agreed to compel Assad to stop bombing the moderate opposition in predetermined geographic zones and to limit the Syrian government’s use of aircraft to humanitarian, medical, and rescue missions. The plan caused an open rift inside the Obama administration, with the White House and State Department supporting the agreement while the Pentagon and Central Intelligence Agency (CIA) opposed it. While Kerry and other advocates argued that it could pave the way for a lasting political solution, U.S. diplomacy once again was not backed by a credible threat to use force, giving Moscow and the Assad regime every incentive to torpedo it.

The cease-fire began in mid-September 2016. Five days in, U.S. airstrikes against Islamic State targets in Deir Ezzor unintentionally killed dozens of Syrian government troops. At the time of the incident, Russian representatives used the deconfliction line to raise objections to the strikes, and U.S. forces immediately stopped their attack. On September 19, the Syrian military—which itself had earlier violated the cease-fire—declared that the cease-fire was over and launched what soon became the final assault on rebel-held parts of Aleppo. The subsequent bombing of a humanitarian aid convoy—reportedly by Russian aircraft—dealt the final blow to the diplomatic track. The tragic turn of events cemented the impression in U.S. policy circles that the Russian military was intent on swinging the conflict decisively in Assad’s favor, rather than supporting initiatives that might reduce the level of bloodshed.

Suborned Into Cooperation

In the meantime, the Russian military frequently treated these high-level diplomatic maneuvers as a mere sideshow, with local commanders intentionally creating dangerous situations to put pressure on Washington or its allies. At the strategic level, the Russian military’s tactics and public posturing put teeth behind its demands to set the terms for U.S.-Russian bilateral military cooperation. Contrived mishaps in the air or on the ground sent a message to U.S. and coalition forces to keep away from certain parts of Syria or to withdraw entirely. Meanwhile, the Russian Defense Ministry issued periodic threats to attack coalition forces and pumped out vast quantities of disinformation about U.S. activities and aims in Syria in order to discredit U.S. policies and create wedges between Washington and its partners.

While honest mistakes may have occurred at times, Moscow’s enthusiasm for leveraging dangerous activities for policy ends created near-constant headaches for U.S. commanders. These actions undercut the standing of figures within the U.S. interagency process who supported testing the Kremlin’s oft-repeated desire for greater cooperation. They also fostered an overall atmosphere of mistrust that made information sharing or crisis management all that much more challenging. Risky Russian maneuvers were frequently tied to narrow goals, such as forcing U.S. counterparts to hold a conversation on one of the deconfliction hotlines, schedule a face-to-face meeting, or adjust a deconfliction agreement in Russia’s favor. (Robert Hamilton, the first head of the U.S. ground deconfliction cell, has memorably described these tactics as a variation on the Russian military’s controversial “escalate to deescalate” doctrine in the nuclear realm.)

As the U.S.-led counter–Islamic State campaign advanced, deconfliction became increasingly relevant for ground operations. Beginning in spring 2017, both pro-regime and coalition-backed forces closed in on the Euphrates River Valley. U.S. and Russian commanders relied increasingly on geographical dividing lines to avoid endangering each other’s forces, initially on an ad hoc basis in 2016 reportedly per a Russian official’s suggestion and then through a series of agreements reached in summer 2017. The deconfliction line broadly followed the Euphrates, south of the city of Tabqa, with the U.S.-backed Syrian Democratic Forces (SDF) claiming the area east of the river and the Assad regime and its allies deploying to the west.

During this period, Russian and Syrian regime units began advertising their desire for control over territory east of the Euphrates, which undermined the deconfliction agreement and created new risks. In mid-June 2017, pro-regime forces attacked an SDF-held town just south of Tabqa. In response, the coalition conducted a show of force with its aircraft and contacted Russian counterparts via the deconfliction hotline to deescalate the situation. But the U.S. request did not stop the attack. A few hours later, a Syrian Su-22 dropped bombs near SDF fighters; a U.S. F-18 jet then shot down the Syrian plane. (After the incident, the Russian Defense Ministry claimed publicly that the coalition had not used the deconfliction channel.) Moscow suspended the memorandum of understanding and heatedly announced that all coalition aircraft operating west of the Euphrates would henceforth be tracked and targeted by Russian surface-to-air missile systems.

In August and September of 2017, Russian officers presented ambitious proposals for the creation of so-called zones of exclusive operations east of the Euphrates. One variant called for exclusive Russian control over territory stretching to the Syrian-Iraqi border, according to Hamilton’s account. In September 2017, another dangerous incident occurred when Russian jets bombed a position where SDF fighters and coalition advisers were known to be located. Again, U.S. efforts to use the deconfliction line failed to stop the attack. Subsequent U.S. communications emphasized a thinly coded message that “any strike against the SDF had the potential to involve direct combat between the U.S. and Russia.” The dispute was ultimately elevated to more senior levels. To deescalate the situation, Dunford and Gerasimov agreed to rely on the U.S. and Russian regional commanders—then Lieutenant General Paul Funk, and Colonel General Sergei Surovikin—for ground deconfliction efforts. As former U.S. special envoy for the Global Coalition to Defeat ISIS Brett McGurk later recounted, when working with the Russians to “draw lines on the map at the Euphrates River,” the U.S. side emphasized: “Look, you don’t cross that river. If you cross that river, we’ll kill you.”

During autumn 2017, Russian and coalition officials also met face-to-face periodically to “adjust and expand deconfliction measures” further down the Middle Euphrates River Valley. Jockeying and misunderstandings around the line continued, with Russian- and Iranian-backed government forces seizing Mayadin and Abu Kamal and conducting occasional airstrikes east of the Euphrates in Deir Ezzor. In November, U.S. and Russian officers agreed on an extension of the Euphrates River as a dividing line and a system of advance notifications prior to any river crossings. The sides also agreed to a limited Russian and Syrian regime presence on the eastern side of the Euphrates, south of Deir Ezzor. (The detachment of Russian mercenaries that attacked the U.S. special forces garrison in Deir Ezzor in early 2018 operated out of this “cut-out,” according to Hamilton.)

Nevertheless, the final months of 2017 were marred by a series of midair close calls and other threatening moves by Russian forces. According to the coalition, Russian and Syrian aircraft flew east of the Euphrates on average six to eight times per day, or roughly 10 percent of all flight activity, despite the existence of the November agreement. In one incident, a Russian Su-25 nearly collided with a coalition F-22 stealth fighter, which had earlier intercepted the Russian jet after it crossed the Euphrates. The U.S. dilemma was spelled out plainly by a coalition spokesman: “It’s become increasingly tough for our pilots to discern whether Russian pilots are deliberately testing or baiting us into reacting, or if these are just honest mistakes. The greatest concern is that we could shoot down a Russian aircraft because its actions are seen as a threat to our air or ground forces.”

Testing U.S. Resolve

Aggressive Russian flight maneuvers in eastern Syria abated in early 2018 as Moscow dealt with the volatile situation in northwest Syria. Nevertheless, the deconfliction mechanism soon faced its most trying—and devastating—moment. In early February 2018, upwards of 500 Russian-speaking fighters, Syrian government soldiers, and pro-regime militia fighters attacked a U.S.-SDF outpost at a former Conoco facility in Deir Ezzor. U.S. soldiers and their Kurdish allies scrambled to defend themselves in the face of a sustained nighttime artillery, mortar, and tank attack by the combined Syrian-Russian force.

Repeated U.S. warnings conveyed via the deconfliction line were shrugged off by Russian officers who disavowed any connection to the Russian-speaking contingent. Multiple deconfliction requests during the firefight also proved ineffectual, according to official Pentagon after-action reports reviewed by the New York Times. A request for a counterstrike was quickly relayed to the senior-most levels of the Pentagon. “My direction to [General Dunford] was for the force, then, to be annihilated,” then secretary of defense James Mattis recounted. “And it was.”

The Russian force reportedly belonged to ChVK Vagner, a private military contractor (PMC) controlled by Yevgeny Prigozhin. A shadowy member of Putin’s coterie, Prigozhin has also been implicated in Russian interference in the 2016 U.S. presidential election. Vagner’s presence in Syria has enabled the Kremlin to minimize casualties among the official Russian military contingent and to create plausible deniability about certain types of Russian operations. Although the use of PMCs in combat zones like eastern Ukraine has been well documented, the Kremlin has gone to considerable lengths to shroud Vagner’s activities in Syria, which are, strictly speaking, forbidden under Russian law.

The February 7 incident was by far the most deadly moment of the Russian intervention. Still, many important questions remain unanswered: Why did the Russian military deny any connection to the assault on the U.S.-SDF position? How high in the Russian leadership would approval have come from for an attack on a location where the presence of U.S. military personnel was so well advertised? Do groups like Vagner report through a parallel chain of command that handles covert action and other risk-intensive activities, or is maintaining plausible deniability the order of the day?

There are signs that the February 7 incident may be connected to the activities of Evro Polis, a Prigozhin-controlled entity that provides security for energy installations in Syria. According to the U.S. Treasury Department, a contract with the Syrian regime has entitled Evro Polis to 25 percent of oil and gas produced at such facilities. The activities of groups like Vagner are, increasingly, one of Russia’s worst-kept state secrets. As Putin explained to the Russian State Duma in spring 2012, PMCs “are definitely an instrument for the realization of national interests without the state’s direct involvement.” Independent Russian military experts such as Aleksandr Khramchikhin have portrayed Vagner in a similar fashion, describing it as “a pseudo-private” company that is directly subordinated to the Russian military. U.S. intelligence intercepts of Prigozhin’s communications reportedly indicate that, ahead of the attack in Deir Ezzor, he notified senior officials in both Moscow and Damascus that the attack had been approved by an unnamed Russian government minister.

At the same time, recent Russian press accounts have suggested that competition over lucrative state contracts is fostering tensions between Prigozhin and the leadership of the Russian Defense Ministry. That raises the possibility that Vagner’s actions in Deir Ezzor were not properly coordinated with local Russian commanders. If so, it is conceivable that the Russian military might have been comfortable washing their hands of the Vagner detachment, especially if it was operating in a purely commercial capacity. Unfortunately, it is impossible to form a definitive judgment either way based on publicly available information. Regardless of whether the attack on the former Conoco facility was motivated by a blend of military and commercial aims, Russian commanders’ handling of the incident exposed the limits of the deconfliction mechanism. It also hardened perceptions inside the Pentagon against pursuing cooperation with a Russian leadership that relishes its ability to challenge the United States via operations below the threshold of armed conflict.

Pushing the Envelope

Unanswered questions about the February 7 attack in Deir Ezzor have also fed anxieties about the security environment at al-Tanf, a remote U.S. military garrison in Syria near the border with Jordan and Iraq. Dangerous incidents at al-Tanf date to the early phases of the Russian intervention. The U.S.-led coalition has used the facility for multiple purposes, including train-and-equip missions for opposition fighters, protection of the Syrian-Jordanian border, and the monitoring of an important Syria–Iraq overland route.

In June 2016, Russian aircraft used cluster munitions to attack the garrison, which had been visited the day before by a group of British special forces. U.S. officers immediately used the deconfliction hotline to call off the Russian attack. Ninety minutes later, Russian planes struck again. Attempts to communicate directly with the pilots via a U.S. military surveillance aircraft using previously agreed-upon emergency frequencies were also ignored. The next month, a nearby refugee camp used by the families of CIA-trained fighters was also attacked by Russian aircraft.

Tensions over al-Tanf have flared periodically ever since. The outpost is surrounded by a 55-kilometer security perimeter that was established by mutual agreement with the Russians. The Russians promised to respect U.S. control over the zone while U.S. forces committed to not support attacks on the Syrian regime by U.S.-backed opposition groups based in the area. Some opposition forces have periodically violated the agreement, using the deconfliction zone as a staging area and de facto safe area. As one unnamed U.S. official put it in an interview with Sam Heller, currently of the International Crisis Group, the Assad regime “probably sees us as duplicitous and liars, and that we’re only there under the pretext of counter-ISIS [Islamic State]. We say we’re there to fight ISIS, but there’s no ISIS there, and [the regime is] getting attacked by the opposition from there.”

Syrian government units and Iranian-backed militias have periodically challenged U.S. forces inside the deconfliction zone. When a column of Syrian regime vehicles and tanks breached the perimeter in mid-May 2017, U.S. officers used the deconfliction line to ask the Russians for help. The Syrian force failed to heed warnings and was eventually attacked by the coalition from the air. Similar strikes were launched in June 2017 against Iranian-backed militia and an Iranian drone, although U.S. officials at the time expressed satisfaction with Russian responsiveness to security concerns that were relayed using the deconfliction line.

More recently, Moscow and the Assad regime have ratcheted up demands for the Trump administration to abandon al-Tanf. These efforts have cynically leveraged dreadful conditions at the isolated Rukban refugee camp, which is located inside the deconfliction zone in a no-man’s-land along the Syrian-Jordanian border. In early September 2018, the Russians used the deconfliction line and a written message to the U.S. regional commander, Lieutenant General Paul E. Funk II, to warn that they were planning a joint attack with Syrian regime forces against militants inside the security zone. Within days of receiving the Russian warning, U.S. commanders quickly arranged live-fire exercises by U.S. Marines at al-Tanf to deter any attack. The commander of U.S. Central Command, General Joseph Votel, then highlighted the U.S. commitment to al-Tanf with a well-publicized visit in mid-October.

National Security Adviser John Bolton indicated in January 2019 that Al-Tanf will be excluded from the planned withdrawal of U.S. forces from Syria. Al-Tanf is “very strategically important in connection with our determination that Iran not achieve this arc of control stretching from Iran thru Iraq into Lebanon and into Syria,” Bolton said. U.S. officials have reportedly informed the Israeli government that U.S. forces will remain at the facility indefinitely, which all but guarantees that it will remain a significant source of danger with Moscow and the Assad regime.


The war in Syria demonstrated that limited forms of U.S.-Russian cooperation, particularly to minimize the risk of inadvertent escalation or accidents, were possible since they required relatively little trust or political capital. Both Moscow and Washington sought to avoid major incidents that might trigger direct military confrontation, which neither side wanted. That paved the way for various deconfliction mechanisms to succeed even though the Russian military’s risky maneuvers frequently sought to test Washington’s resolve and limits. While the deadly events in Deir Ezzor appear, at first glance, to be a failure of the deconfliction mechanism, U.S. commanders’ decisiveness and the lethality of U.S. military capabilities have taught Moscow a rather important lesson.

It is also worth posing the question whether Washington and Moscow missed an opportunity to forge a closer military-to-military relationship in Syria. Or was this always an illusory prospect? To put it plainly, both the Obama and Trump administrations have been deeply skeptical about the reputational risks of cooperation—let alone whether Russian counterparts could be trusted. In the words of Obama’s former NSC point person for the Middle East, Robert Malley, “Russia’s been very adept at playing for time, saying things that sounded promising, then over time eroding whatever agreement had been reached. We caught on to it pretty quickly.”

Both Obama and Trump also demonstrated great reluctance about being drawn into the Syria conflict. They feared, rightly, that direct U.S. military involvement would touch off a no-win escalatory dynamic and that the Assad regime, assisted by its generous patrons in Tehran and Moscow, would always be able to overmatch any U.S. efforts. That, in turn, would only increase the suffering of Syrian civilians and expand the threat of terrorism. Given such stark choices, top policymakers and the Pentagon quite understandably preferred to focus on a counter–Islamic State mission that was limited in scope with an achievable set of benchmarks.

During both Obama’s and Trump’s time in office, the Kremlin has demonstrated a remarkable knack for filling the vacuums created by U.S. policymakers in the Middle East and beyond, usually on the cheap. The success of the Russian military campaign in Syria revealed that Moscow understands leverage. From the moment the Kremlin intervened in Syria, it had far more leverage than the United States. It was sharply focused on building more advantages over time, using a combination of diplomacy, military force, and nonconventional tools such as ragtag mercenaries operating with the thinnest veneer of plausible deniability. But the United States failed to follow suit. To the extent Washington thought it had leverage, it was in the hope that Putin was looking for a quick exit (which was not a crazy idea in 2015 and 2016, but was ultimately incorrect) and the effectiveness of the counter–Islamic State mission in northeast Syria. On the whole, the Obama administration usually negotiated from a position of weakness, and Moscow took full advantage. Washington must build leverage and match means to ends in order to succeed in comparable situations going forward.
Common secondary interests were not sufficient to sustain complex military and diplomatic cooperation, given the largely adversarial nature of the U.S.-Russian relationship. Both Moscow and Washington may have wanted to target terrorists, but successful counterterrorism cooperation ultimately depends on an ability to share sensitive intelligence and targeting information. That proved impossible, given the chronic distrust between intelligence services, the Russians’ and the Assad regime’s ruthless targeting of U.S.-backed opposition groups, and the divergence of other goals in Syria. Russia’s use of indiscriminate force, its alignment with a regime that had used chemical weapons, and its vastly different definition of who was a terrorist in Syria rendered counterterrorism cooperation an unpalatable prospect.

The Trump administration conceivably could have tried to work with Congress to loosen the restrictions on coordination contained in the NDAA, but the Pentagon showed zero interest in such initiatives, making them a nonstarter. Still, there is a strong case to be made for increasing the intensity of communication between military establishments going forward as well as the number of active dialogues. Fostering multiple lines of communication and expanding their focus to cover other issues, such as in-depth advance notification of upcoming exercises, could help to reduce misperception and misunderstandings on both sides.

The Russian penchant for transactional diplomacy continues to surface, including most vividly at the disastrous Trump-Putin summit in Helsinki. Putin’s call for joint efforts on postconflict reconstruction and refugee return demonstrated both a degree of Russian overconfidence and a misplaced sense that the Trump administration was, at long last, prepared to cooperate in Syria on Moscow’s terms. Although Trump himself has showered praise on Putin as a potential partner, U.S. officials derailed both of Putin’s initiatives, drawing attention yet again to the fundamental disconnect between U.S. and Russian long-term goals in Syria.

Both sides, arguably, have an interest in making sure that the lessons learned from the deconfliction effort are not discarded as a result of the Trump administration’s planned withdrawal from Syria. In recent years, the Kremlin has resisted instituting similar efforts in other theaters where the risk of inadvertent escalation or military incidents is greatest. Yet the stubborn fact remains that such dangers are largely the product of deliberate Russian efforts. By increasing the risk of military confrontation, Moscow believes that it can intimidate the West into simply backing off. The seemingly thankless task before Western policymakers remains to manage such provocations carefully and to prove them wrong.