Over the last four years, I helped lead the global response to the rise of the Islamic State (ISIS)—an effort that succeeded in destroying an ISIS “caliphate” in the heart of the Middle East that had served as a magnet for foreign jihadists and a base for launching terrorist attacks around the world. Working as a special envoy for U.S. Presidents Barack Obama and Donald Trump, I helped establish a coalition that was the largest of its kind in history: 75 countries and four international organizations, their cooperation built on a foundation of U.S. leadership and consistency across U.S. administrations. Indeed, the strategy to destroy the ISIS caliphate was developed under Obama and then carried forward, with minor modifications, under Trump; throughout, it focused on enabling local fighters to reclaim their cities from ISIS and then establish the conditions for displaced people to return.

From the outset, the strategy also presumed that the United States would remain active in the region for a period after the caliphate’s destruction, including on the ground in northeastern Syria, where today approximately 2,000 U.S. Special Forces hold together a coalition of 60,000 Syrian fighters known as the Syrian Democratic Forces, or SDF. But in late December 2018, Trump upended this strategy. Following a phone call with his Turkish counterpart, Recep Tayyip Erdogan, Trump gave a surprise order to withdraw all U.S. troops from Syria, apparently without considering the consequences. Trump has since modified that order—his plan, as of the writing of this essay, is for approximately 200 U.S. troops to stay in northeastern Syria and for another 200 to remain at al-Tanf, an isolated base in the country’s southeast. (The administration also hopes, likely in vain, that other members of the coalition will replace the withdrawn U.S. forces with forces of their own.) But if anything, this new plan is even riskier: it tasks a small cohort of troops with the same mission as the current U.S. deployment in northeastern Syria, which is ten times as large.

Much remains uncertain about the U.S. withdrawal. But whatever the final troop levels turn out to be, Trump’s decision to significantly reduce the American footprint in Syria is unlikely to be reversed. The task now is to determine what should come next—what the United States can do to guard its interests in Syria even as it draws down its military presence over the coming months. The worst thing Washington can do is to pretend that its withdrawal—whether full or partial—does not really matter, or that it is merely a tactical move requiring no change in overall objectives. The strategy that Trump dismantled offered the United States its only real chance to achieve a number of interwoven goals in Syria: preventing an ISIS resurgence, checking the ambitions of Iran and Turkey, and negotiating a favorable postwar settlement with Russia. With U.S. forces leaving Syria, many of these goals are no longer viable.

Washington must now lower its sights. It should focus on protecting only two interests in Syria: preventing ISIS from coming back and stopping Iran from establishing a fortified military presence there that might threaten Israel. Without leverage on the ground, reaching even those outcomes will require painful compromises. But the alternative, in which the United States pretends that nothing has changed, fails to achieve even these modest goals, and further undermines its credibility in the process, is far worse. This is a bitter pill to swallow after the progress of the last four years. But stripped of other options, the United States must swallow it nonetheless.

DEFEATING THE CALIPHATE

In September 2014, ISIS was on the march. The group controlled nearly 40,000 square miles of territory in Iraq and Syria, an area roughly the size of Indiana and home to some eight million people. With over $1 billion per year in revenue, the group used this self-described caliphate as a base to plan and execute terrorist attacks in Europe and urged its sympathizers to do the same in the United States. Closer to home, ISIS murdered, raped, and enslaved those it considered heretics or infidels: Christians, Kurds, Shiites, and Yazidis, and also Sunnis who disagreed with the group’s ideology. Despite this brutality—and in part because of it—the group exerted a powerful pull. Between 2013 and 2017, more than 40,000 people from over 100 countries traveled to Syria to join ISIS and other extremist groups fighting in the Syrian civil war.

I was on the ground in Iraq in the summer of 2014, when ISIS took the city of Mosul and then advanced on Baghdad. Even as the U.S. embassy began evacuating staff in preparation for the worst, American diplomats were getting ready to help the Iraqis fight back. Over the ensuing months, we assembled a broad coalition of governments united in their opposition to ISIS. The coalition’s plan was to combine military operations against the group with innovative humanitarian and stabilization initiatives, which would ensure that those displaced by ISIS could obtain basic shelter and return home after the fighting had ended.

The U.S. campaign against ISIS is not—and never was—an "endless war."

From the start, U.S. diplomats made clear that this would not be an open-ended campaign to build nations or reshape the Middle East. The goal was to destroy ISIS and help local people organize their own affairs in the aftermath of the group’s defeat. In this, the campaign was a success. Over the next four years, ISIS lost nearly all the territory it once controlled. Most of its leaders were killed. In Iraq, four million civilians have returned to areas once held by ISIS, a rate of return unmatched after any other recent violent conflict. Last year, Iraq held national elections and inaugurated a new government led by capable, pro-Western leaders focused on further uniting the country. In Syria, the SDF fully cleared ISIS out of its territorial havens in the country’s northeast, and U.S.-led stabilization programs helped Syrians return to their homes. In Raqqa, ISIS’ former capital, 150,000 civilians out of a displaced population of over 200,000 had returned by the end of 2018.

In short, the U.S. campaign against ISIS is not—and never was—an “endless war” of the sort that Trump decried in his February 2019 State of the Union address. It was designed from the beginning to keep the United States out of the kind of expensive entanglements that Trump rightly condemns. Iraqis and Syrians, not Americans, are doing most of the fighting. The coalition, not just Washington, is footing the bill. And unlike the United States’ 2003 invasion of Iraq, this campaign enjoys widespread domestic and international support.

Toward the end of 2018, the campaign was approaching an inflection point. The physical caliphate was near defeat, and the coalition was transitioning to a fight against a clandestine ISIS insurgency. Although U.S. policymakers had planned for this transition, there was some debate within the government about how long the United States should stay in Syria, as well as what its ultimate objectives there should be. Some U.S. officials, especially those in the Pentagon, were focused on completing the original mission: the enduring defeat of ISIS. In Syria, this meant destroying the caliphate and then staying for a period to help the SDF secure its territory and deny ISIS the ability to return. Yet others, particularly John Bolton, Trump’s national security adviser, believed that U.S. forces should remain in Syria until all Iranian forces left and the country’s civil war was resolved. This would have represented a vast expansion of the mission and required an indefinite commitment of U.S. troops, something Trump opposed.

No one in the U.S. government had seriously discussed near-term withdrawal, let alone the idea that Washington could simply declare victory over ISIS and then leave Syria. On December 11, 2018, I stood at the State Department podium and explained the United States’ then official policy on Syria: “It would be reckless if we were just to say, well, the physical caliphate is defeated, so we can just leave now.” Eight days later, Trump did just that, declaring via Twitter that “we have won against ISIS” and that “our boys, our young women, our men—they’re coming back, and they’re coming back now.” This announcement left the campaign in disarray and Washington’s allies in disbelief. U.S. officials, including me, scrambled to explain the abrupt change of course to our partners. After four years of helping to lead the coalition, I found it impossible to effectively carry out my new instructions, and on December 22, I resigned.

BEGINNING OF THE END

By the time Trump made his announcement, ISIS’ caliphate was down to its last few towns and Syria was witnessing its lowest levels of violence since the onset of the civil war in 2011. The country was settling into what U.S. officials called “the interim end state,” temporarily divided into three zones of great-power influence.

The first and largest zone is controlled by the Syrian state. This zone encompasses about two-thirds of the country’s territory, perhaps 70 percent of its population, and most of its major cities, such as Damascus and Aleppo. It receives heavy military and financial support from one great power, Russia, and one regional power, Iran. The second zone is the opposition enclave in northwestern Syria. Much of this zone is now dominated by al Qaeda’s Syrian affiliate, Hayat Tahrir al-Sham, with Turkish-backed opposition groups controlling the rest. The Turkish military protects a cease-fire line, which Ankara negotiated with Iran and Russia, separating the western edge of the Turkish zone from the areas controlled by the Assad regime.

The third zone is dominated by the SDF and backed by Washington and its allies. Once the heart of the ISIS caliphate, this area comprises nearly one-third of Syria’s territory, with significant energy reserves, great agricultural wealth, and a population of nearly four million. France, the United Kingdom, and the United States all have special forces on the ground in this zone, and the broader coalition helps protect its airspace and contributes to stabilization programs. The United States and an allied Syrian opposition group also control al-Tanf, which was formerly an ISIS garrison town.

As violence in Syria plummeted over the course of 2018, the boundaries between these zones solidified, setting the table for great-power diplomacy. With forces on the ground and influence over one-third of the country, the United States was in a position to play an important role in shaping postwar Syria.

GREAT-POWER DIPLOMACY

A major priority for American diplomats was to reach a settlement with the only other great power in Syria, Russia, about the ultimate disposition of territory in the U.S. zone of influence. Washington had been holding bilateral talks with Moscow on Syria since the beginning of Russia’s military intervention, in 2015. Initially, the goal was to prevent accidental clashes between U.S. and Russian forces. Over time, these talks became a forum for Washington to draw clear boundaries delineating areas that would be off-limits to Russian and Syrian forces and to militias backed by Iran. This worked because the United States was willing and able to enforce these boundaries: In May 2017, American jets bombed Iranian-backed militias as they approached a U.S. position near al-Tanf; the following month, U.S. jets shot down a Syrian fighter jet as it crossed into the northeastern zone near a U.S. position. And in February 2018, U.S. forces destroyed a group of Russian mercenaries who were attempting to capture an oil field held by SDF and American troops.

By the fall of 2018, the United States was preparing for intensive negotiations with Russia along two sequential tracks. On the first track, Washington would try to encourage the Russians to compel the Syrian regime to cooperate in the UN-backed peace talks known as “the Geneva process.” This process had been in place since 2012, and I had grown skeptical that it would produce results. But for the first time in years, a number of favorable developments—the reduction in violence throughout Syria, the United States’ presence on the ground, and the strengthening of the U.S.-Russian diplomatic channel—had combined to give the process a chance for at least some success.

If the Geneva process did not produce a breakthrough, U.S. diplomats had prepared a second track for negotiating directly with the Russians to broker a deal between the SDF and the Syrian regime. This deal would have provided for the partial return of Syrian state services, such as schools and hospitals, to SDF-controlled areas—an inevitability, unless the United States and its allies were willing to midwife a ministate in northeastern Syria—while granting basic political rights to the region’s population. U.S. officials referred to this outcome as “the return of the state, not the return of the regime.” Any deal would have also allowed the United States access to airspace and small military facilities in this area in order to maintain pressure on ISIS and prevent the group’s resurgence.

Such an arrangement would have met the aspirations of the Syrians who had fought alongside the coalition and ensured their continued safety. It would have also returned basic state services to the northeast, helping the local population and reducing the risk of an insurgency against SDF and U.S. troops. Russia, moreover, was beginning to accept that the U.S. presence in northeastern Syria would remain until the “final defeat” of ISIS—a phrase that appeared in a joint communique from Trump and Russian President Vladimir Putin in late 2017. Moscow recognized that a stable postwar settlement would require compromises between Damascus and the SDF. By the end of 2018, the contours of an imperfect but acceptable arrangement were beginning to emerge.

CAGING IRAN

The U.S. strategy toward Tehran was more adversarial. Iran’s military presence in the Syrian regime’s zone of influence is significant; if entrenched, it would constitute a major threat to Israel and Jordan, two vital U.S. allies. Tehran also harbors expansionist ambitions in Syria: its proxy forces have sought to infiltrate the U.S. zone in the northeast, as well as the area surrounding the al-Tanf garrison, which sits on a major roadway between Damascus and Basra, in southern Iraq. They have been deterred only by the presence of U.S. troops and the threat—or, in the case of al-Tanf, the use—of force.

Bolton’s declaration that U.S. troops would stay in Syria until all the Iranians left was never realistic. Even with unlimited resources—which Trump was not prepared to commit—the United States could not hope to fully expel the Iranians from Syria. Iran’s military partnership with Syria dates back to the early 1980s; Tehran sees the country as one of its most important allies and is willing to pay a high price to preserve its foothold there. Hollow saber rattling serves only to weaken U.S. credibility and distract from more realistic goals: containing Iran’s presence in Syria, deterring its threats to Israel, and using diplomacy to drive a wedge between Tehran and Moscow.

In the spring of 2018, Putin publicly stated that Russia wanted to see all foreign military forces (meaning Iranian, Turkish, and U.S. forces) leave Syria after the end of the civil war. U.S. diplomats began to exploit this opening, demanding that Russia prove that it could remove the Iranians from key areas of the country, such as the region bordering Israel and Jordan. As part of these negotiations, the Russians claimed that they could keep Iranian-supported units at least 50 miles from the Golan Heights and agreed to allow UN peacekeepers to monitor a demilitarized zone there. If the Russians could accomplish this to the satisfaction of the Israelis, Washington said it might be willing to discuss a partial withdrawal from some of its areas.

The United States coordinated its approach with Israel, which in 2017 began launching air strikes against Iranian military assets in Syria that it considered a threat. Washington had no legal authority to target Iranian forces inside Syria except in cases of self-defense, but Israel had every right to deny Iran the ability to use Syrian territory for its missile systems and other offensive technology. The combination of Israeli hard power, American diplomacy, and the U.S. military presence gave Washington a powerful bargaining chip with the Russians. Putin views Russia’s relationship with Israel as central to his Middle East strategy. The United States was never going to remove every Iranian from Syria. But by working with the Israelis and leveraging its own influence in Syria, it could have secured a measure of Russian cooperation in deterring Iranian expansionism.

OTTOMAN DREAMS

The U.S. presence in Syria was also critical for managing relations with Turkey, which had been a problematic partner from the outset of the anti-ISIS campaign. In 2014 and 2015, Obama repeatedly asked Erdogan to control the Turkish border with Syria, through which ISIS fighters and materiel flowed freely. Erdogan took no action. In late 2014, Turkey opposed the anti-ISIS coalition’s effort to save the predominantly Kurdish city of Kobani, in northern Syria, from a massive ISIS assault that threatened to end in a civilian massacre. Six months later, Turkey refused coalition requests to close border crossings in towns that had become logistical hubs for ISIS, such as Tal Abyad—even after U.S. diplomats had told the Turks that if they did not control their border, defeating ISIS would be impossible.

Faced with Turkey’s intransigence, the United States began to partner more closely with the Syrian Kurdish fighters, known as the People’s Protection Units (YPG), who had defended Kobani. The YPG struck the first blow against ISIS in Syria, and it soon proved adept at recruiting tens of thousands of Arabs into what would later become the SDF.

Turkey objected to U.S. support of the SDF. Ankara claimed that the group’s Kurdish component was controlled by the Kurdistan Workers’ Party (PKK), a Kurdish separatist group that has fought an on-again, off-again war against Turkey for nearly four decades. (The United States designated the PKK as a terrorist organization in 1997.) Although Washington never found any instances of YPG members crossing the border to fight in Turkey, nor evidence that the PKK had operational control over the SDF or that U.S.-supplied weapons were making their way into Turkey, U.S. policymakers took pains to address Ankara’s concerns. The United States limited its military aid to the SDF; as a result, the group’s fighters went into combat without body armor or helmets and with only limited antimine equipment. (On one of my visits to Raqqa, I learned that SDF fighters purchased flocks of sheep to detect and ignite ISIS mines.) For months, the United States attempted to placate Erdogan by delaying urgent SDF operations such as the campaign to eject ISIS from the Syrian town of Manbij, which the group was using as a hub to plan and execute attacks in Europe. Washington even sent its best military strategists to Ankara, where they tried to devise a plan to liberate Raqqa with fighters from the Turkish-backed Syrian opposition. In the end, it became clear that a joint plan with Turkey would require as many as 20,000 U.S. troops on the ground. Both Obama and Trump rejected that option, and in May 2017, Trump decided to directly arm the YPG to ensure that it could take Raqqa from ISIS.

American diplomats were able to manage the resulting tensions with Turkey thanks to the U.S. military’s presence in Syria. If Turkey said there was a problem on the border, U.S. forces could ensure that the border remained calm and stable. (The United States also repeatedly invited Turkish officials to come into northeastern Syria and see the situation for themselves, which they pointedly refused to do.) When Turkey threatened to attack the Kurds across the border, as it often did, Washington reminded Ankara that U.S. troops were on the ground there, too. And the United States assured Erdogan that it would deter any demonstrated threat to Turkey from Syria. As long as U.S. troops were present, there was no reason for the Turkish military to intervene, and Ankara knew that jeopardizing American lives would carry grave consequences for its relations with Washington.

The withdrawal of U.S. forces, however, removes this deterrent. There is now a risk that Turkey could launch an incursion into northeastern Syria similar to the one it carried out in January 2018 in Afrin, a Kurdish district in northwestern Syria not protected by U.S. troops. There, the Turkish military, working with its Islamist allies in the Syrian opposition, attacked the YPG, displaced over 150,000 Kurds (nearly half of Afrin’s population), and repopulated the province with Arabs and Turkmen from elsewhere in Syria. This operation was not a response to any genuine threat but a product of Erdogan’s ambition to extend Turkey’s borders, which he feels were unfairly drawn by the 1923 Treaty of Lausanne. I have sat in meetings with Erdogan and heard him describe the nearly 400 miles between Aleppo and Mosul as a “Turkish security zone,” and his actions have backed up his words. In 2016, Turkey deployed its military forces north of Mosul without the permission of the Iraqi government or anyone else; further deployments were blocked only by the presence of U.S. marines. Erdogan would now like to repeat his Afrin operation in the northeast. This would involve sending Turkish forces 20 miles into Syria, removing the YPG (and much of the Kurdish civilian population), and establishing a so-called safe zone.

The U.S. military presence bought time for U.S. diplomats to secure a long-term arrangement that might reasonably satisfy Turkey while deterring Erdogan’s grand ambitions and protecting the SDF and its Kurdish fighters. Withdrawing before such an arrangement is in place risks a catastrophe—a Turkish invasion that would lead to massive civilian displacement, fracture the SDF, and create a vacuum in which extremist groups such as ISIS would thrive.

A fighter from the Turkish-backed Free Syrian Army in Afrin, March 2018 Khalil Ashawi / Reuters

THE ARAB ROAD TO DAMASCUS

The U.S. military presence in Syria was also important for managing Washington’s relations with the Arab states. The specter of three former imperial powers—Iran, Russia, and Turkey—determining the fate of Syria, a majority Arab state, has unsurprisingly generated Arab pushback, particularly from Egypt, Jordan, Saudi Arabia, and the United Arab Emirates (UAE). And with much of the Syrian opposition now either dominated by Islamists or reduced to the status of a Turkish proxy, these states have begun their efforts to return Damascus to the Arab fold.

The United States has opposed its Arab allies’ push to normalize ties with Damascus, judging that this would reduce the pressure on Syrian President Bashar al-Assad to participate in the Geneva process. As long as U.S. troops were on the ground in Syria and leading a successful campaign against ISIS, American diplomats could speak with authority when asking their Arab partners to refrain from reengaging with Assad: the U.S. presence provided a check against the Iranian and Turkish expansion that the Arab states feared. As recently as December 2018, Washington had assured its Arab allies that U.S. troops would remain on the ground in Syria for a significant period of time. This assurance helped secure large investments from Saudi Arabia and the UAE in support of civilian stabilization efforts in areas once held by ISIS, including the city of Raqqa.

Trump’s promised withdrawal has upended this situation. The United States will now struggle to convince its Arab allies that it is a committed player in Syria. And since Iran and Turkey are advancing agendas in Syria that diverge sharply from those of the Arab states, it will be hard for U.S. diplomats to tell their Arab partners not to pursue their own interests as they see fit, including by working with the Syrian regime. (Washington could threaten to sanction the Arab states, but such threats are a sign of weakness when used against friends.) It was no surprise that the UAE reopened its embassy in Damascus shortly after Trump announced the U.S. withdrawal. Other Arab states can be expected to follow its lead.

HARD TRUTHS

The U.S. deployment in Syria made it possible for the United States to stand toe to toe with Russia, contain Iran, restrain Turkey, hold the Arab states in line, and, most important, prevent a resurgence of ISIS. Trump’s initial order to fully withdraw U.S. troops forfeited all those advantages. His recent amendment to that order, which permits 200 troops to remain in the northeast and 200 to remain at al-Tanf in the hope that other coalition troops will eventually make up the balance, could make matters even worse.

Trump’s new plan has not halted his original withdrawal order. Over the coming months, the United States will be significantly reducing its troop levels in Syria without knowing whether the coalition will send replacements, which will make planning difficult and increase the risk to those troops that remain. Other coalition forces, moreover, are unlikely to deploy in sufficient numbers. In Iraq, the coalition has 22 contributing military partners. In Syria, it has three: France, the United Kingdom, and the United States. The French and British deployments are small and, thanks to domestic political pressures in both countries, won’t be increased by much, if at all. To make matters worse, the mission for the 200 U.S. troops in the northeast will apparently be expanded to include not only the defeat of ISIS but also the maintenance of a safe zone in the Turkish border region and the defense of the U.S. zone against Iranian, Russian, or Syrian infiltration. This is too much for 200 troops to accomplish; it would have been difficult even for 2,000. Asking such a small force to pursue such an expansive mission introduces major risks that could be avoided by maintaining the U.S. presence at its current level.

The United States will fail if it continues to pursue grand objectives in Syria.

The best thing that Trump could do would be to reverse his withdrawal order. But if he does not, the United States cannot pretend that by leaving a handful of troops in Syria, it can avoid the need to rethink its strategy. Washington must accept some hard truths. The first is that Assad is not going anywhere. He is a mass murderer and a war criminal, but at this late stage, there is no chance that the United States or anyone else will unseat him. Washington does not need to accept Assad’s rule or engage with his regime, but it should no longer drain U.S. credibility and prestige by insisting that he must go—or that he must reform his own regime out of existence in Geneva. And although the United States can continue to pressure Damascus with sanctions, the economic pain it can inflict pales in comparison to what the regime has already suffered. Since 2011, Syria has seen the steepest GDP collapse of any country since Germany and Japan at the end of World War II. Washington should use targeted sanctions to pursue more limited goals, such as ensuring that Syrian refugees can return from Jordan and Lebanon and that the UN is allowed to operate throughout the country, including in the SDF-controlled areas of the northeast. Using sanctions in pursuit of unachievable aims, such as the removal of Assad, will only create black markets that benefit extremists and increase the suffering of ordinary Syrians.

A second, related truth is that the Arab states will now reengage with Damascus. Resistance to this trend from Washington will only frustrate the Arab states and encourage them to conduct their diplomacy behind Washington’s back. A better approach would be for the United States to work with its Arab partners to craft a realistic agenda for dealing with Damascus—for instance, by encouraging the Arab states to condition their renewed relations with Syria on confidence-building measures from the Assad regime, such as a general amnesty for military-age males who fled the country or joined opposition groups and now want to return to regime-controlled territory. Limited, conditional Arab openings to Damascus might also begin to dilute Iran and Russia’s monopoly of influence in Syria.

The United States must also accept that Turkey, although a treaty ally, is not an effective partner. U.S. diplomats continue to hope that by working with Turkey on Syria, they can break Ankara’s drift toward authoritarianism and a foreign policy that works against U.S. interests. They cannot. Turkey was a problematic ally well before any disagreement over Syria. Over the past decade, Ankara has helped Iran avoid U.S. sanctions, held U.S. citizens hostage, and used migration as a tool to blackmail Europe. More recently, it has begun to purchase Russian antiaircraft systems over the objections of NATO and has actively supported—along with China, Iran, and Russia—President Nicolás Maduro’s authoritarian regime in Venezuela. Turkey wants U.S. support for its project to extend its territory 20 miles into northeastern Syria, even as it refuses to do anything about al Qaeda’s entrenchment in northwestern Syria. Washington should have no part of this cynical agenda. It should make clear to Ankara that a Turkish attack on the SDF—even after the U.S. withdrawal—will carry serious consequences for the U.S.-Turkish relationship.

Finally, the United States must recognize that Russia is now the main power broker in Syria. Washington has no relations with Damascus or Tehran, so it will have to work with Moscow to get anything done. Russia and the United States have some overlapping interests in Syria: both want the country to retain its territorial integrity and deny a safe haven to ISIS and al Qaeda, and both have close ties with Israel. The Syrian crisis cannot be resolved without direct engagement between Moscow and Washington, and the United States should isolate the Syrian problem from other aspects of its troubled and adversarial relationship with Russia.

BACK TO REALITY

Given these hard truths, the United States will fail if it continues to pursue grand objectives in Syria. Instead, Washington should realign its ends with its newly limited means. It must focus now on two interests: denying Iran a fortified military presence that might threaten Israel and preventing a resurgence of ISIS.

Denying Iran a fortified military presence is a far more modest aim than the ones stated by Bolton and Secretary of State Mike Pompeo. Before Trump issued his withdrawal order, Bolton had declared that U.S. forces would stay in Syria “so long as the Iranian menace continues throughout the Middle East.” Speaking to an audience in Cairo this past January, Pompeo declared that the United States would “expel every last Iranian boot” from Syria—this shortly after Trump had ordered every last American boot to leave. These were not realistic objectives before Trump’s withdrawal decision, and they ring even more hollow afterward.

What the United States can and should do instead is lend diplomatic support to Israel as its military denies Iran the ability to use Syria as a staging ground for missile strikes against Israel. This is a goal shared by Russia, which is anxious to preserve good relations with the Israeli government and wants to prevent Syria from becoming a battleground between Israel and Iran. The aim of forestalling Iranian military entrenchment in Syria could serve as the basis for trilateral diplomacy among Israel, Russia, and the United States. If pursued smartly, such diplomacy could also begin to drive a wedge between Russia and Iran over Syria.

It will be more difficult for the United States to prevent a resurgence of ISIS. The SDF now controls the former caliphate’s territory, but its resources are meager. It confronts a hostile Turkey to the north, an adversarial Iran and Syrian regime to the south, and a restless population of millions in the area it controls. The SDF is also holding thousands of hardened ISIS prisoners, including over 1,000 foreign fighters, who, if released, could become the nucleus for a revived ISIS. American military forces, with positions across northeastern Syria and unique capabilities in intelligence and logistics, serve as an essential support for the SDF and allow it to operate as a cohesive force. If the United States withdraws—or reduces its military presence to a shell of the current one—its ability to support the SDF will atrophy, leaving the group more exposed in the outer reaches of its territory. A reduction in U.S. support will also increase the risk that the SDF’s multiple ethnic and regional components will begin to fracture or find new allies—Iran and the regime for some, Turkey for others. And although ISIS is weakened, it is still a ruthless and disciplined actor. It will rapidly move to fill any vacuum left in Syria’s northeast.

As the United States leaves, the SDF will need a new benefactor that can help it maintain its ability to hold northeastern Syria and protect it from Iran and Turkey. Unfortunately, the only viable candidate for this role is Russia. Moscow can offer the SDF a measure of military and diplomatic support and help the group strike a deal with the regime that would incorporate the SDF into the Syrian army and secure political rights for the population in northeastern Syria. The SDF has already offered to become a branch of the Syrian army in exchange for some political recognition of its local councils. Such an outcome is unappetizing. But it is likely the only way to preserve stability in the northeast while keeping ISIS on the back foot. Such an arrangement would not be unprecedented: former anti-regime opposition groups have been reorganized under a Russian-commanded Fifth Corps, now operating in southern Syria. For these fighters, and the Arab states that backed them, this was a better option than military defeat or subjugation by Iran. (Syria is the land of bad options.) The United States can still help shape a deal along these lines, but it should do so soon, as its influence will only diminish over the coming months.

These revised goals are modest. They reflect the unavoidable fact that Trump forfeited U.S. leadership at a decisive moment in the campaign, to the benefit of Iran, Russia, and Turkey. American policymakers will have to accept that U.S. influence in Syria is on the wane and rethink their objectives accordingly. The best way to salvage the situation is for U.S. leaders to realign their ends, ways, and means with a focus on what really matters to Washington—preventing Syria from becoming a staging ground for attacks against the United States or its allies. This is an important and achievable goal. The main obstacle to its realization is denial.