Syria is now nine years into a civil war that frequently promises, but never manages, to wind down. President Bashar al-Assad has retaken much of the country, but broad swaths remain combat zones. Just this month, Assad’s forces, with Russia’s backing, advanced in Idlib Province, the opposition stronghold in northwestern Syria, after a nearly ten-month-long offensive. Since December 1, 2019, more than 800,000 Syrians have fled their homes.

Assad may have gained territory, but his regime remains deeply fragile, and the regions under its control are unstable and growing more so. This war is not one that Assad can decisively win, even with help from Iran and Russia.

The United States must recognize that the conflict in Syria is unlikely to end in the near future. The prospect of more war is devastating, but it means that Syria’s fate is far from decided. Leveraging American diplomatic, economic, and military capabilities, which dwarf those of every other actor in Syria, could change the trajectory of the conflict, help contain the humanitarian crisis, and lay important groundwork for an eventual political transition. With so much still at stake, even limited U.S. involvement could make a difference.

THE REGIME’S HIGH-WATER MARK

Assad cobbled his forces together with help from Iran and Russia. But the coalition’s military is overextended. Damascus and its partners gambled that by stretching a thin layer of control over as much terrain as possible, they could convince the international community to accept a regime “victory.” In fact, the coalition hoped that other countries would help it consolidate its power by investing in reconstruction projects that could repay Iran and Russia and finance the corrupt patronage system through which Assad rules.

The plan nearly worked. By late 2018, the Syrian regime had advanced far enough that some countries began to reconsider their opposition to Assad. The United Arab Emirates reopened its embassy and invested in reconstruction projects. Saudi Arabia and some European countries considered following suit. By contrast, in perhaps its most undervalued decision in the region, the administration of U.S. President Donald Trump held the line. It refused to concede to a false regime victory and instead added sanctions on Damascus and refocused the West’s attention on a diplomatic process aimed at reaching a political settlement that would hold Assad’s regime to account and deny it reconstruction funds. Stubbornness bought important time.

The fragility of the regime’s control is increasingly apparent. In the southern province of Daraa, where Syria’s original 2011 revolution was born, a new uprising has begun. Sustained protests have sent a clear message that Assad has failed to break his opponents’ will. Insurgents have resumed attacking positions held by Assad, Iran, and Russia at levels approaching those of 2011. For the first time in years, the attacks have spread to the Syrian capital in Damascus and to parts of the surrounding Rif Damascus region. Meanwhile, the Islamic State (also known as ISIS) is quickly resurging in regime-held central Syria. The group has assaulted vital oil infrastructure and temporarily seized facilities. Such activity suggests major ISIS attacks are still to come.

Assad and his backers have no serious answer to this rising instability. Instead, they continue to expand their already thinly controlled territory. Through their offensive in Idlib, regime forces have seized three important cities and gained full control of the Damascus–Aleppo highway. But the process has been grinding and costly even with the support of Russian airpower and proxy units: the Assad regime has taken high casualties and has had to repeatedly mobilize new conscripts.

Assad and his backers have no serious answer to rising instability.

Northeastern Syria has become another drain on the pro-regime coalition’s assets. The United States scaled back its forces in the area in October 2019, allowing Turkey to surge over the Syrian border. In order to gain leverage over Turkey, Russian and Syrian regime forces moved in and established a new military presence in the northeast, further stretching pro-regime resources.

Russia’s approach reflects its limits. Russian airpower is effective at destroying hospitals and depopulating cities, but these tactics will not defeat an insurgency. Most Russian ground forces in Syria are military police whose primary job is restoring basic law and order. Counterinsurgents, by contrast, must protect civilians while fighting complex battles to defeat insurgents, often in urban areas. Moreover, Russia’s military police lack credibility among Syrians, who have seen Assad undermine reconciliation deals that Russia has brokered in the past.

FINANCIAL COLLAPSE

Not only has the pro-regime military effort likely reached its peak, but the Syrian economy is collapsing. The Syrian pound fell dramatically from a 2014 rate of roughly 179 to the dollar to more than 1,000 to the dollar by late January. The sharp decline is partly the result of an economic collapse in neighboring Lebanon and partly a function of U.S. sanctions on Iran. The latter have forced Iran to cancel Syria’s credit line and to cut back on oil transfers to the regime.

Assad is struggling to pay warlords and finance military campaigns at a time when the insurgents are imposing ever greater costs. Food and fuel prices have risen sharply, sparking protests against the government’s economic policies; although still small in loyalist areas, these protests seem likely to grow. Assad is desperately attempting to head off the deepening economic crisis, in part by seizing the financial assets of business leaders close to the regime. These seizures threaten to alienate loyalists and undermine local patronage structures in unstable regions.

Assad is struggling to pay warlords and finance military campaigns.

Syria’s economic situation is going to get worse. In December, the U.S. Congress authorized sweeping sanctions against any entity providing financial, military, or technological support to Assad’s government, his military, or Iranian and Russian entities in Syria. The restrictions are potentially game changing. The Trump administration supported the legislation and intends to move forward. By June 2020, the Treasury Department must evaluate whether Syria’s central bank is complicit in money laundering, in which case a cascade of sanctions will go into effect this summer. At a minimum, those sanctions would severely restrict the regime’s resources, likely forcing it to suspend its military offensives and deepening instability in regime-controlled areas.

The United States hopes that economic pressure will compel Assad to submit to negotiations. Yet chances of a far-reaching settlement are slim. Assad and his backers may attempt to grant Trump a superficial deal in return for sanctions relief, but such a gamble is unlikely to work. Once sanctions are implemented, Trump has the authority to unilaterally lift them if he determines that the regime and its allies have ceased human rights violations and taken “verifiable steps to establish accountability for war crimes.” This bar is extremely high and would be difficult to bypass. The existing diplomatic stalemate will likely continue.

THE WAR TO COME

The economic collapse of regime-held Syria would perpetuate and expand Syria’s wider, multisided war. Numerous actors stand poised to take advantage of any shift in the balance of power within the country, and underlying sociocultural rifts will shape the war’s evolution: ISIS and al Qaeda extremism continue to drive long-term conflict, and Iran is sowing new social divisions by attempting to convert Syrians to Shiism and to teach them Farsi in parts of southern and eastern Syria. Kurdish forces in the northeast are locked in a ferocious struggle with Turkey, which has invaded and effectively annexed large parts of the border region and intends to resettle one million Arab refugees there. The Kurdish forces are fighting back as an insurgency. This conflict is partly cultural: both the Kurdish forces and Turkey are trying to transform the parts of Syrian society that are under their influence in ways that will drive long-term instability even if the immediate fighting stops.

Numerous actors stand poised to take advantage of any shift in the balance of power within the country.

As the pro-regime military effort wanes, Turkey’s leverage in Syria will increase. Turkey has already deployed significant reinforcements to Idlib to prevent and possibly reverse pro-regime gains. And it has retaliated for multiple Syrian regime attacks on its soldiers and vowed to respond by “any means necessary” to future incidents. Russia and Turkey will attempt to de-escalate, but the more the pro-regime war effort suffers under economic pressure, the less incentive Turkey will have to grant concessions. This change in the power balance could itself drive more conflict.

ISIS and al Qaeda are also well positioned to exploit Assad’s weakness. ISIS is already surging in regime-held Syria and expanding its campaign in Kurdish-held areas, where the U.S. drawdown has weakened security. Meanwhile, al Qaeda-linked groups have an army of approximately 20,000 fighters in Idlib, where they are making a substantial profit. Al Qaeda will remain a powerful insurgency even if Idlib falls.

SHAPING THE ENDGAME

The United States does not need a massive military force in Syria to shape the war’s trajectory, but its current presence is insufficient. U.S. troops continue to help Kurdish forces to disrupt ISIS networks, and U.S. strikes continue to disrupt al Qaeda attack cells. But current troop levels won’t be enough to defeat the ISIS insurgency or reverse al Qaeda’s rise in Syria, much less accomplish wider goals, such as stabilizing the Kurdish-dominated northeast or supporting Turkish efforts to contain the humanitarian crisis in the northwest.

The collapse of the Syrian economy and growing discontent among Assad loyalists—as well as a Turkish military intervention that has pro-regime forces badly overstretched—have created an opening. Renewed commitment to Syria will be uncomfortable, given Americans’ concerns about open-ended conflicts and coming just five months after the Trump administration’s decision to shift most U.S. troops in Syria across the border to Iraq. But the United States must act.

The U.S. troops that were redeployed to Iraq should be returned to Syria’s northeastern region. Turkey’s efforts to repel Assad’s forces and protect civilians in northwestern Syria deserve American support. But U.S. efforts are best concentrated in the northeast. In close coordination with its allies, the United States should work to stabilize the region and to assist reconstruction, development, and resettlement efforts. Syria’s northeast has a relatively strong economy compared with economic conditions in regime-controlled areas, and focused investment will help establish it as a model of safety, prosperity, and good governance—a credible alternative to Assad that could help pave the way for a political transition. The United States has a real opportunity to change the course of the brutal Syrian war and, potentially, to shape its endgame.