Joseph V. Micallef is a best-selling military history and world affairs author, and keynote speaker. Follow him on Twitter @JosephVMicallef.

The Syrian civil war is now in its seventh year. The war has resulted in the deaths of roughly 500,000 people. More than one million have been injured, and around 12 million people, about half of the country's population, have been made refugees. About 5.5 million people are external refugees, with 3.5 million of those now in Turkey and the balance elsewhere in the Middle East or Europe, and 2.5 million have been displaced within Syria.

The overriding issue of that conflict -- whether Bashar al-Assad's government would continue to rule Syria -- has been settled. It will.

The intensity of the fighting has diminished, and the pace of military operations is lower. The war, however, is far from over.

Moreover, there are a range of secondary issues that were bound up with the civil war, which remain unresolved. The success of the Assad regime and its Russian and Iranian backers notwithstanding, the civil war is now largely stalemated, as are many of the secondary issues that were linked to it.

The Syrian Jigsaw

The Syrian army and its proxies have taken control of most of Syria west of the Euphrates. This zone includes Syria's five largest cities: Aleppo, Damascus, Latakia, Homs and Hama. The U.S.-backed Syrian Democratic Forces (SDF), which consist largely of Kurdish troops, control the northeast end of the country along a line running roughly from Jarabulus to Manbij to Raqqa to Deir ez-Zor.

Turkish troops and Turkish-backed militias control Afrin province, a predominantly Kurdish region, and the area along the Turkish-Syrian border, extending to the western bank of the Euphrates across the river from Jarabulus and south to Abu al-Zandeen.

The remnants of the Free Syrian Army and various rebel groups, including a large number of Islamic fundamentalist groups, have withdrawn into the Idlib governorate, one of the 14 governorates in Syria. This is the last rebel-controlled region of any size in Syria. The area is largely controlled by two Islamist groups: Hayat Tahrir al-Sham and its Islamist partner, and often rival, Ahrar al-Sham.

Hayat Tahrir al-Sham (Organization for the Liberation of the Levant) is the latest rebranding of what was previously the al-Qaida-affiliated al-Nusra Front. The group began as al-Qaida in Syria and has gone through six different name changes as it has tried to disassociate itself from al-Qaida and its origins. It has received financial assistance from Qatar.

Western governments have branded Hayat Tahrir as a terrorist group and as an al-Qaida proxy. Hayat Tahrir's training camps have been attacked by U.S. and coalition air forces. There are approximately 100 Islamist groups affiliated with and operating under the Hayat Tahrir banner, although the composition of the organization, and the affiliation of militants with specific groups, can be very fluid.

Ahrar al-Sham (Harakat Ahrar al-Sham al-Islamiyya/Islamic Movement of the Free Men of the Levant) is also a coalition of various Islamist and Salafist groups. On occasion, it has also operated in coalition with other jihadist groups under the banner of the Syrian Liberation Front. Ahrar has received strong financial and military support from Turkey.

On Sept. 17, 2018, Turkey and Russia announced they had agreed on the establishment of a demilitarized zone in Idlib governorate that would be jointly patrolled by Turkish and Russian troops. The zone would have separated Syrian troops from rebel-held areas. The demilitarized zone is still in force, although it has been violated repeatedly by both sides.

Why the Stalemate Will Continue

Turkey's intervention in the Syrian civil war was prompted by a desire to use the Free Syrian Army, as well as various Islamist groups, to topple the Assad government. The intervention of Russia and Iran made that objective untenable. In the meantime, the success of the Syrian Democratic Forces, and the prospect of a quasi-autonomous Kurdish state along the Syrian-Turkish border, forced Ankara to revise its objectives to focus on preventing the organization of a Kurdish government.

At present, Turkey has few options. A direct attack on the SDF would bring it into direct conflict with the U.S. and its coalition allies. At one point, it seemed that Ankara had persuaded the Trump administration to withdraw the troops embedded in the SDF and allow Turkey a free hand in dealing with the Kurds.

The Trump administration, however, reversed course. Although a partial U.S. withdrawal now seems to be in progress, the role of U.S. advisers is being taken up by French and British forces. Turkey cannot launch an all-out attack against the SDF without risking a definitive break with the U.S. and its other NATO allies.

At the same time, it has no easy options elsewhere in Syria. A larger military intervention would be highly unpopular in Turkey and would likely bring it into direct conflict with Russia.

The various rebel groups and Turkish-backed militias have succeeded in pushing back attempts by the Syrian Army to advance, but they lack the strength to topple the Assad regime. A Turkish withdrawal would result in its proxies and rebel allies being overrun by Syrian military forces and would be deeply embarrassing to Ankara and its aspirations for leadership within the Muslim world.

Simply put, Turkey is too far into Syria to back out, but lacks sufficient forces to alter the situation on the ground. Turkey's economic troubles further constrain Ankara's options. For now, Turkey has a seat at the negotiations table, but its hand will likely grow weaker over time.

Iran played a critical role in supporting the Assad government and in shaping the outcome of the civil war. It provided financial and military aid to Damascus. Its Quds Force was heavily involved in organizing and arming pro-Assad militias in Syria and in providing intelligence to the Assad government and its military. In addition, Iranian proxies, most of all Hezbollah, fought alongside Syrian military forces during the war.

Tehran saw Syria as the linchpin that would hold together a zone of friendly, Iranian-influenced governments running from Iraq to the Gaza Strip. Most importantly, Tehran wanted to secure a ground route from Iran across Iraq and Syria that would allow it to directly resupply Hezbollah, as well as establish permanent military bases in Syria. Iran has not been successful in leveraging its support of the Assad government into accomplishing either objective.

First, renewed U.S. sanctions on Iran have cut deeply into Iranian oil exports and Tehran's finances. Iran has had to cut back on the amount of aid that it can give the Assad government and, more importantly, on the financial support that it gives its proxies such as Hezbollah and the Quds Force-led Syrian militias.

Secondly, both Moscow and Damascus have pushed back on Tehran's plans for permanent military bases in Syria. Both governments see such bases as a hindrance to normalizing Damascus' relations with the rest of the world. Those bases that it did establish have been subject to attacks by the Israeli Air Force and, beyond a token condemnation, have precipitated little response from Moscow

Moreover, with the survival of the Assad regime now certain, Russian and Iranian interests are beginning to diverge. Moscow's rapprochement with Riyadh, and the de facto inclusion of Russia into OPEC, is worrisome for Tehran. Effectively, OPEC has now become a Russian-Saudi-run organization. Moscow needs high oil prices. Cooperation with Saudi Arabia can help achieve that. There is little influence that Iran can exert on oil prices, short of attacking tanker traffic in the Persian Gulf.

Moreover, Washington has made it clear that it remains concerned about Tehran's influence in Syria, and has broadly hinted that it would be open to recognizing the Assad regime in return for sharply reducing or eliminating Tehran's role there. The risk of a U.S.-Russian deal on Syria at its expense isn't lost on Tehran.

For now, it's unlikely that Tehran will see its role in Syria sharply diminished. The Assad government has a vested interest in keeping Iran close to offset Russian influence. Tehran may not be leaving Syria anytime soon, but it has not been able to leverage its support for Assad as much as it had hoped. The Shiite arc of Iranian influence is turning out to be less permanent than Tehran had envisioned.

The role of the Kurds in Syria is equally stalemated. The SDF does not have the military strength or hardware to take on Turkey for control of the Kurdish enclave in Afrin. The U.S. has made it clear to the Kurds that it would not support the SDF in a conflict with Turkey. Without American supplies, and more importantly American air power, the SDF has little chance of prevailing over Turkey's military and its proxies.

The Assad government has not pursued military operations against the SDF, preferring instead to drop hints that it is open to a political accommodation with the Kurds at some point in the future. The Kurds have ended up with a de facto self-governing region in Syria, even if it doesn't conform to the Kurdish ethnic geography. That's no small feat, but it falls short of Kurdish aspirations, and the SDF have few options for achieving those goals.

The United States' primary motivation for intervening in the Syrian civil war was to destroy the Islamic State (ISIS). With the fall of Raqqa and the overrunning of the last remaining ISIS-controlled areas in the Euphrates Valley, it has accomplished this. On the other hand, while the Islamic State has been destroyed, there are still thousands of ISIS militants in Syria and Iraq, and the organization still has tens of thousands of committed supporters. Moreover, its influence around the world is as strong as ever.

The Pentagon has been wary of repeating the mistakes of the Obama administration in Iraq and disengaging prematurely. The U.S. won the last round of the conflict with ISIS, but the war with the Islamic State is far from over.

Washington remains concerned about the influence that Tehran has in Iraq and Syria. The U.S. has considerable influence in Baghdad but little influence in Damascus. It has little leverage in Syria to reduce the Iranian role there, short of a deal with Moscow or continuing to raise the economic pressure on Iran.

Moscow, on the other hand, finds itself in the enviable role of being the one essential partner that each side needs to fulfill its broader objectives. Continued Russian support is essential for the Assad regime to stay in power. Likewise, Moscow's support, or at the very least acquiescence, is essential for Turkey, Iran or the Kurds to meet their broader objectives in Syria. It's equally unlikely that the U.S. will succeed in limiting Iranian influence in Syria without first striking a deal with the Russians.

Finding itself the essential partner, Moscow has little interest in seeking a quick resolution to resolving the remaining issues in the Syrian civil war. Once the Kremlin picks sides, it will invariably lose some of its leverage. Better to let the issues remain unresolved and, in doing so, maximize its influence with all of the parties concerned.

The Syrian civil war may be in its endgame, but there is little chance that any of the remaining issues will be resolved soon.

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