Charles Lister is senior fellow at the Middle East Institute and author of The Syrian Jihad: Al-Qaeda, the Islamic State and the Evolution of an Insurgency.

After six years of committing unrestrained and uninhibited violence against his own population, the regime of Bashar Assad experienced the first pangs of justice early Friday morning Syria time, as 59 American Tomahawk cruise missiles struck the strategically vital Al-Shayrat air base in the center of the country. Syrian military aircraft, hardened hangars and refueling facilities were among the targets of America’s first explicit attack on the Assad regime.

This was a justified, proportionate and necessary response for what had been a flagrant war crime committed three days earlier, when chemical nerve agents were dropped by planes from Al-Shayrat onto residential areas of Khan Sheikhoun, a town in Syria’s northwest. As men, women and children alike lost control of their muscles, succumbed to uncontrollable convulsions and began foaming from the mouth and nose, emergency and medical personnel rushed to the scene. They then found their facilities targeted in a series of follow-up bombings, possibly by Russian jets. At least 87 people lost their lives and more than 300 others were injured. This was merely the latest of dozens of chemical attacks conducted by the Assad regime since 2012, the worst of which killed more than 1,400 people east of Damascus in August 2013.


It was that heinous act in 2013, conducted within eyesight of Assad’s own presidential palace, that famously crossed then-President Barack Obama’s self-declared “red line.” That same attack led to Obama’s subsequent decision to back away from the use of force in favor of an agreement brokered by Russia to remove Syria’s chemical weapons stockpiles in their entirety, a move that angered America’s Arab allies and effectively ended any potential U.S. efforts to threaten Assad’s rule. At the drop of the hat, overt affiliation with the United States became a politically toxic label that moderate opposition groups sought either to hide or to dissolve.

Recent events have not only demonstrated the clear failure and abrogation of that agreement by the Assad regime, but the presence of Russian troops and possibly also aircraft at the Al-Shayrat airbase appears to suggest that Russia was not only aware of Assad having retained some portion ofhis chemical weapons, but may also have been in a position to prevent their use.

That the fledgling Trump administration determined it necessary to respond to this latest criminal act represents a significant turning point in the Syrian crisis, though the exact implications remain to be seen. At this point in time, the cruise missile attack on Al-Shayrat remains an isolated punitive act: a warning to Assad and his patrons that brazen war crimes will now be met with military consequences. It is now the heavy responsibility of the Trump administration to ensure that this enforced “red line” be maintained. Reports of localized chlorine attacks on opposition areas of Damascus later on Friday indicated that this new line in the sand may be tested sooner than some may have expected. Punitive military actions are a clear form of deterrence that will work only if further violations meet with the same or a similar response.

A core dynamic at play here pertains to Russia, which was warned of U.S. plans to attack Al-Shayrat but whose entire presence in Syria is predicated on propping up Assad and covering for his criminal actions. In the immediate aftermath of the chemical attack on Khan Sheikhoun, a humiliated Russia was forced to concoct an illogical story, every facet of which was either swiftly disproved or dismissed as laughable by experts and journalists on the ground. With U.S. intelligence now investigating whether Russia had been involved in the use of chemical weapons in Khan Sheikhoun, Russia’s emphatic rhetoric and talk of threats is almost certainly cover for its lack of options and the fact that it finds itself having to blindly protect a global pariah. When the likes of Iran, North Korea and Venezuela are your only true defense, your claims of righteousness are to be taken with a sizable grain of salt.

Having taken military action, the U.S. has an opportunity to exploit its newfound leverage. Left alone, the Syrian conflict has many years left, but its consequences continue to worsen, with nearly 500,000 Syrians now dead and 11.3 million others either internally displaced or refugees. Military efforts against the Islamic State have achieved substantial success, but terrorism remains one of many symptoms of a much broader crisis, the single root cause of which remains the Assad regime. There is simply no way of ignoring that reality.

So what now? Assad cannot and will never put Syria back together again, but partition is not an answer. Foreign intervention for rapid regime change promises only further chaos, but determined U.S. leadership backed up by the credible and now proven threat of force presents the best opportunity in years to strong-arm actors on the ground into a phase of meaningful de-escalation, out of which eventually, a durable negotiation process may result. This is something Obama never understood: His efforts to broker peace failed because he refused even to consider threatening war. Every feeble threat given from an Obama podium effectively amounted to a further emboldening of the Assad regime’s sense of immunity and its free hand to murder its people en masse.

Bringing peace to Syria will undoubtedly necessitate a further strengthening of the U.S. posture toward the Syrian situation and toward Russia, Iran and other involved states. More military strikes and other assertive acts of diplomacy will be inevitable but if anything is now clear, it is that the U.S. has more freedom of action in Syria than the Obama administration was ever willing to admit. Opponents of limited U.S. intervention who have long and confidently pronounced the inevitability of conflict with Russia are now faced with the reality that Moscow failed to lift a finger when American missiles careered toward Assad regime targets. For now, that discovery was made through a tactical reaction to a brazen war crime, but a holistic strategy must now be developed that treats all threats emanating from Syria as individual components of a single problem: the Assad regime.

Russia’s seat on the U.N. Security Council and its conventional military assets make it appear to be the key obstacle to progress, but Iran is arguably a greater challenge. For Russia, Assad is disposable—an asset to potentially be haggled over at the negotiating table. But for Iran, the survival of the Assad regime remains an existential issue. While Russians privately acknowledge that Syria’s army retains no more than 20,000 offensively capable and deployable personnel, Iran-backed Syrian paramilitary and foreign militia forces may now number over 150,000 men. Some of those groups are designated terrorist organizations, legally no different from al Qaeda or ISIS. As one prominent Russian in Moscow recently told me in Europe, even Russia’s own Spetsnaz special forces have come to respect one such Iran-backed terrorist group — Hezbollah — more than the Syrian Army itself.

Whether Friday’s cruise-missile strike was part of a more holistic strategy or not, the consequences of military action now demand broader strategic consideration. This newly demonstrated U.S. policy of containment and deterrence will be tested and as Nikki Haley, the U.S. ambassador the U.N., made clear, “We are prepared to do more.” Such statements must be backed up by action, if and when necessary. Assad, Russia, Iran and Hezbollah are not about to give up the fight, but they are now dealing with a markedly different and more complex set of assessments. Gone are the days of acting with impunity. Their actions are now under multiple microscopes.

The U.S. must also now seek to engage and manage its own allies in the region, particularly Turkey, which appears to be re-embracing a more overtly pro-opposition stance, only weeks after resuming arms supplies to opposition groups in Syria’s northwest. The Pentagon, which views its impending operation to retake Raqqa—a capital of the dwindling ISIS caliphate—as its top priority, understandably fears being dragged into a broader mission of stabilizing Syria itself. But ISIS is the bastard child of Assad’s misrule: Syria will never be stable while he remains in power and the longer he sticks around, the more extremists will reap the rewards of his brutality by escaping from justice and ensuring their narratives thrive among the disenfranchised.

The choice is not and has never been a binary one between Assad and ISIS, as some have tried to claim. Syria remains a country of many communities and many perspectives. Of a population of roughly 23 million people, no more than 20,000 (0.09 percent) have chosen to join Al Qaeda or ISIS, according to privately discussed estimates held by U.S. intelligence officials. Therefore, U.S. policy is best served by securing a future for the remaining 99.91 percent. With newfound leverage and a growing coalition of countries announcing their support for stronger action on Assad, the U.S. has an opportunity now to set Syria on a path toward something better. It will take time and resources, and likely many more risks, but that must surely hold better prospects than leaving the country to war criminals and their blind defenders.