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

The battle for Raqqa is entering its fifth and final phase. Before the end of 2017, it is likely that Islamic State (IS) militants will have been expelled from Raqqa. This will not be the end of the war against the Islamic State. It is likely that one final battle remains, the battle for Deir ez-Zur. Nonetheless, the fall of Raqqa is a development that will likely have long-term consequences for the political organization of eastern Syria. Already the major actors in the Syrian conflict have begun to position themselves for the post-IS reality. In the process, they are highlighting the geopolitics of the region.

The Campaign: Operation Wrath of Euphrates

The Raqqa campaign, codenamed Operation Wrath of Euphrates, began on November 6, 2016. It is one element of Operation Inherent Resolve, the U.S.-led operation comprised of some 30 countries working together as the Combined Joint Task Force (CJTF) to roll back and eradicate the Islamic State, its leadership and its militants.

The offensive against the Islamic State (IS) capital of Raqqa is occurring simultaneously with the campaign by the Iraqi Army, various Iranian backed Shiite militias and the CJTF, to retake the city of Mosul in northern Iraq’s Nineveh province from IS. The Mosul campaign is in its ninth month. IS forces in the city have been surrounded and the territory still under their control has been reduced to a small pocket in the historic old city of Mosul on the west bank of the Tigris. It’s expected that the remaining IS militants in the city, estimated variously at between 500 and 3,000, will be overrun in the next 30 to 45 days.

The force attacking Raqqa consists of a multi-ethnic, multiparty alliance, operating loosely under the umbrella of the Syrian Democratic Forces (SDF), and numbers between 30,000 and 40,000 soldiers. According to the SDF, 70 percent of the overall force consists of Sunni Arabs, many of whom are drawn from the surrounding area. That percentage is probably on the high side, but, nonetheless, there is a sizeable Arab contingent among the fighters. More importantly, the Sunni Arab segment of the coalition is being trained to takeover security and civil administration once IS has been expelled and the Kurdish portion of the coalition has been withdrawn.

The multi-ethnic aspect of the SDF is critical. Initially, the SDF was composed almost entirely of Syrian Kurds and a smattering of other ethnic groups. There was a concern both within the SDF and its U.S. backers that military operations by the SDF in predominantly Sunni Arab areas would result in a sectarian backlash and might even create support for IS. While the SDF still has a predominantly Kurdish core, Sunni Arab elements are now more prevalent and they have been given a highly visible role in the future administration and security of Sunni areas.

Roughly two-thirds of the force is comprised of militia drawn from the Kurdish People’s Protection Union (YPG) and the Women’s Protection Units (YPJ). The latter is an all-female military organization that parallels the combat role and organizational structure of the YPG. Notwithstanding their name, both the YPG and the YPJ have enlisted a large non-Kurdish component. The YPJ, for example, has an Arab brigade made up of over 1,000 Arab women.

The YPG was formed in 2004, as the military wing of the Democratic Union Party (PYD). The PYD, considered a Kurdish leftist organization, is closely associated with the Turkish based Kurdistan Worker’s Party (PKK). Historically the PKK was considered a pro-communist, anti-Western organization; strongly aligned with Russia and, prior to that, the Soviet Union.

The PKK has been conducting a campaign of violence against the Turkish government since 1978. Its ideology was a combination of Kurdish nationalism and revolutionary socialism. Its original intent was to create an independent, Marxist-Leninist inspired, Kurdish state in the region. Since 1999, it has moved away from its Marxist-Leninist roots and has muted its call for an independent Kurdish state. Both Turkey and the U.S. have labeled the PKK as a terrorist organization.

In addition to the YPG and YPJ contingents in the SDF, there is also the Raqqa Hawks militia, a group of around 1,000 Arab fighters drawn from the Raqqa area. There is also the Elite Forces (EF) unit of the Free Syrian Army (FSA) of al-Shaitat and Shammar. The EF was originally drawn from the Deir ez-Zur and Hasakah governates and is comprised primarily of members of the al-Shaitat tribe. This tribe extends over most of eastern Syria and even into portions of Iraq. The EF unit is believed to have between 650 and 3,000 fighters. They are not officially part of the SDF but coordinate military operations with them.

The al-Sanadid Forces (Forces of the Brave) is a militia based on the al-Shammar tribe. It also extends across eastern Syria and pockets of Iraq and Saudi Arabia. Its historic capital, the Emirate of Jabal Shammar, was incorporated into Saudi Arabia, a fact that has made the al-Shammar both vehemently anti-IS and also anti-Saudi. Its strength is estimated at around 2,000 men.

In addition, there are approximately 3,000 fighters that are drawn from the Deir ez-Zur and Manbij Military councils. They are two of the four local military councils comprised primarily of Sunni Arabs organized by the SDF, at the urging of the U.S. in 2016, to conduct local military operations and takeover security responsibilities from the SDF once the region had been liberated. The other two councils are the al-Bab and the Jarabulus military councils. Both of which function in a similar capacity.

There are approximately four thousand fighters organized into village militias that are drawn from pro-SDF tribes in the region. These militias are being supplied arms and training by the SDF. Finally, there are also about 500 fighters from the HXP or Self Defense Forces. These are a multi-ethic territorial defense militia that have been conscripted in the Kurdish controlled cantons that make up the Democratic Federation of Northern Syria, the de facto autonomous region often called Rojava.

The level of U.S. Forces with the SDF is unclear, but has been estimated at between 3,000 and 5,000 troops. There are a variety of Special Forces whose strength has been estimated at between 500 and 900 soldiers. Approximately 500 U.S. Special Forces were involved in the final assault to take control of the Tabqa Dam in April.

U.S. Marines with the 11th Marine Expeditionary Unit have also been deployed to support the SDF. These troops include an artillery battery of M-777 howitzers. These guns fire 155 mm shells. They are manned by Battalion Landing Team 1st Battalion 4th Marines. Additional units have been tasked with providing security and handling logistics for the artillery battery.

There are also U.S. personnel embedded with the SDF, as well as in various training roles. Finally, there are an additional 5,000 or so paratroopers from the 82nd Airborne that have been staged to Kuwait, which are available for deployment in either Syria or Iraq if needed.

Islamic Forces in Raqqa and the surrounding region are estimated at around 10,000 to 20,000, with approximately 5,000 fighters in the city of Raqqa itself and the balance to the south and east of the city. Most of the IS leadership, including its media operations, is believed to have transferred itself to Deir ez-Zur or the surrounding region. That means the fall of Raqqa, while symbolic, will not mark the decisive end of the campaign against the Islamic State.

The Raqqa campaign has had five distinct phases so far. Phase 1, 2 and 3 were designed to isolate Raqqa by cutting it off to the north, west and east. Phase 3 and 4 focused on taking control of the Tabqa dam and the city of Tabqa as well as the Tabqa military air base. IS has threatened numerous times to either destroy the Tabqa dam or open its flood gates and release the waters of the 200 sqm Lake Assad behind it to flood the city of Raqqa and the Euphrates Valley below it.

In addition, phase 4 tightened the encirclement of Raqqa and brought SDF troops to the city’s outskirts. There have been persistent reports that Washington has plans to base U.S. air forces at the Tabqa air base. The Pentagon has declined to comment on those reports. Phase 5 began on June 6, 2017, with the announcement by the SDF that it had launched the Battle of Raqqa. The attack commenced simultaneously from the north, east and west. Raqqa is located on the north bank of the Euphrates. IS still controlled the south bank of the Euphrates, but U.S. air forces had destroyed all the bridges across the Euphrates linking Raqqa with the south bank, effectively isolating it from the south as well.

At last report, June 23, SDF forces were advancing along the southern bank of the river and had reportedly reached the eastern edge of Karsat al-Farj, the zone between where the old and new bridges into Raqqa were located. As of June 23, it appeared that SDF forces were less than a half-mile away from completely encircling Raqqa.

In the meantime, on the north bank of the river, SDF forces have secured the districts of al-Mishlab, al-Sabahiya (an industrial area), al-Romaniya and Sinaa, as well as portions of the Hattin district. Approximately 400 ISIS militants have been reported killed. The bulk of IS forces in Raqqa are in the old city opposite the southern bank of the Euphrates. As in the Mosul campaign, this will likely be the last area cleared as the rabbit warren of narrow streets and overhanging buildings will prove to be the hardest to secure.

Since the beginning of the Raqqa campaign, the SDF has liberated an area of 2,900 sqm and freed over 200 villages controlled by Islamic State forces. In addition, it seized control of the former Syrian Air Force base at Tabqa and the strategically important Tabqa and Baath dams. The destruction of those dams would have produced catastrophic flooding in the Euphrates valley.

When Operation Wrath of Euphrates was launched in November 2016, it appeared that it would quickly become a symbolic race to see who would free Raqqa with all the attendant symbolism of a proxy contest between the U.S., Russia and Turkey. Instead, the SDF has emerged with the dominant position, having effectively surrounded Raqqa. More importantly, Turkey lacks any clear path to Raqqa that would not bring it into direct conflict with Syrian military forces.

On March 2, 2017, the Manbij Military Council, a predominantly Arab group that had been set up to take over security from the SDF, turned over a vast area west of Manbij that had been liberated by the SDF, to the Syrian Army. The transfer, done at the urging of the U.S., was ostensibly to create a buffer zone between the SDF and Turkish backed rebels.

In doing so, however, the SDF ensured that the Syrian military would control the M4 highway and highway 216 as well as the access to Highway 4. These highways are the logical axis of advance for Turkish forces and their associated militias. At this point, any Turkish advance toward Raqqa would bring it into immediate conflict with Syrian military forces and, more importantly, their Russian backers.

In the meantime, the Syrian army, led by their elite Tiger Unit, had advanced from the west of Raqqa to Maskanah and south toward the Ithriyah-Tabqa road (highway 42). By June 18 they had seized the Rusafa road junction and were just west of the Rusafa oil field. The oil field is Islamic State's largest remaining oil field. Given that SDF forces have already virtually encircled Raqqa, it's unclear what role Syrian military forces will play in the battle for Raqqa.

It’s possible, though highly unlikely, that SDF forces may withdraw from a portion of the perimeter to give the Syrian army an axis of advance into Raqqa. The road junction at Rusafa would also allow Syrian military forces to bypass the SDF surrounding Raqqa and advance directly toward Deir ez-Zur for what will likely be the last major battle of the anti-Islamic State campaign. Control of the road junction also blocks the advance of SDF troops to the south.

The Geopolitics of Eastern Syria

In the meantime, although the final collapse of Islamic State in eastern Syria is hardly imminent, the jockeying for position between Russia, the U.S. and Iran and their proxies has already begun. Eastern Syria has about 70 percent of Syria's oil reserves. In addition, there are several critical transportation axes, the M20, Highway 6, the M4 and Highway 4, which connect Syria's major cities in the west with Raqqa and Deir ez Zour and go on to link Syria with Iraq and create a continuous transportation link between Beirut and Tehran.

There are several questions worth raising about the geopolitics of eastern Syria. First, what exactly are the Kurds doing there? Raqqa is not a historical Kurdish region. There are virtually no Kurds living there. The SDF has already made it clear that once IS has been defeated, Kurdish elements of the SDF will withdraw and turnover security and administration to Sunni Arab militia forces that are part of or allied with the SDF.

IS no longer poses a strategic threat to Syrian Kurds or to the territories they ultimately wish to retain control of. That threat now comes from Turkey and from Assad’s Syrian government. So why are Syria’s Kurds willing to spill their blood to defeat an enemy that no longer poses much of a strategic threat and to conquer territory they will quickly give up control over? The answer is that they are there as an American proxy. They are fighting the battle that otherwise the U.S. could only fight by directly deploying U.S. troops in theater.

The question is what has the U.S. promised Syria’s Kurds in return for becoming a U.S. proxy in the Syrian ground war against Islamic State? Officially, the U.S. is opposed to an independent Kurdish state in Syria. Then again, this is the Middle East where nothing is ever as it appears and what you say and what you do often have little relationship to one another.

The U.S. has become the primary source of arms and training for the SDF. Without the SDF, the U.S. would be forced to rely primarily on U.S. and coalition air power and a variety of Special Forces in theater. Those are considerable assets, but not enough to shape the ground war in Syria or to give the U.S. a meaningful military role in determining its outcome.

Ankara keeps insisting that it has U.S. assurances that it will disarm the Syrian Kurds once IS had been defeated. It’s hard to imagine that happening or that the Kurds, surrounded by enemies would willingly give up their U.S. supplied arms. Especially if Washington is toying with the idea of establishing an airbase in eastern Syria.

The Kurds have a long history of being sold out by the West, dating back to the Versailles Conference following World War I. They enjoy strong political support on Capitol Hill, so any gambit to sacrifice the Syrian Kurds in exchange for other political or diplomatic objectives would get significant pushback from both Republicans and Democrats in the U.S. Senate.

For their part, the Kurds are understandably cautious, and while signing on as American proxies they have also kept open their historic links to Russia. In fact, the Syrian Kurds are the only actor in the Syrian war that enjoys the support of both Russia and the U.S. What is clear is that in the complicated three-way relationship between the U.S., Turkey and the Syrian Kurds, someone, at some point, is going to be seriously disappointed with the final outcome.

Iran, for its part, wants to control at least one of the road networks linking it via Iraq with Syria and Lebanon. An overland axis will make the resupply of Hezbollah in Lebanon far easier. Raqqa and Deir ez-Zur are the two key transportation hubs through which the roads connecting Iraq and western Syria pass. Manbij is also a critical road junction, but the M4 highway east of the Euphrates is controlled by the Kurds.

Much has been written of late about the “Shiite arc” that runs from Iran across Iraq, Syria and Lebanon down to Gaza. At the moment, this is a political concept rather than a tangible physical construct. The Sunni Arab triangle in Iraq and the Sunni areas of eastern Syria effectively are a blocking force to a continuous physical transportation link across the ground of the Shiite arc.

The upper two thirds of the Euphrates Valley, the portion that bisects eastern Syria and western Iraq, is almost entirely Sunni Arab in composition. The portion that isn’t is predominantly Kurdish. The remaining ethnic groups range from Sunni Turkoman to Assyrian Christians and Yazidi, among others. None are particularly sympathetic to Tehran’s Shiite agenda. A continued military presence for the SDF, especially one that has a significant Arab contingent in the Sunni Arab areas and is backed by a local U.S. air presence, would prove to be a significant obstacle to Tehran’s plans for the region.

To date, the U.S. has been opposed to the dismemberment of either Syria or Iraq. The fact is, however, that, in what historians will undoubtedly call the Muslim Civil War of the 21st century, the Arab Sunni lands of eastern Syria and western Iraq create a significant geographic obstacle to the expansion of Iranian power and influence across the Shiite arc.

This region’s borders with both Saudi Arabia and Jordan and the presence of significant oil and gas, gives it both access to exterior transportation links that not dependent on either the Shiite governments in Syria or Iraq as well as a basis for further economic development. So too, does the ability to access the waterflow of the Euphrates. Washington’s relations with Baghdad would deteriorate sharply if the U.S. was to advocate the creation of a Sunni Arab state in the region, on the other hand such a state would clearly be in America’s long-term interest.

The Assad government, having now retaken Aleppo and having gained the upper hand against the Syrian rebels, is looking to reassert its authority over eastern Syria. The region’s oil and gas wealth is a powerful inducement, as is Damascus’s desire to restore its control over all the historic Syrian state. It also would benefit from direct transportation links between Syria and Iran.

Both Iraq and Syria are failed states. It’s not clear that once Islamic State has been defeated, either country will succeed in reintegrating their historic Sunni Arab regions, especially the ones that were under the control of IS, back into their respective former countries. Both Baghdad and Damascus, along with Tehran, share a common interest in preventing the emergence of a Sunni state across eastern Syria and western Iraq.

Like Damascus, Baghdad wants to restore its territorial integrity and solidify its control of Iraq’s territory. In particular, it wants to be able to exert enough authority across the Sunni triangle to prevent the emergence of new subversive and radical jihadist movements.

Moreover, the physical damage inflicted, first by IS and then by the war that has been fought to defeat it, has caused enormous damage. Neither government has the resources to foot the multi-billion-dollar reconstruction that will be needed to rebuild the region and to take care of what will end up as millions of displaced persons. Should either government marginalize the reconstruction effort or aid to the Sunni Arab inhabitants of the region, it will only serve to encourage support of yet another radical insurgency.

Finally, there is Russia. Moscow has achieved its immediate objectives in Syria. It has ensured that the Assad regime will survive, and it has secured military bases in Syria that allow it to better project military power, albeit modestly, in the region. While the loss of eastern Syria would weaken the Assad regime, and it would likely ensure the continuation of an insurgency in the Sunni areas controlled by Damascus, it would also ensure continued Syrian and Iranian reliance on an active Russian role, as well as open opportunities for Moscow to further ingratiate itself with Baghdad. Keeping the Middle East pot boiling is very much in the Kremlin’s interest and ensures it an ongoing role there.

The defeat of the Islamic State is in its final phase. It’s likely that in the next 12 months IS will lose any semblance of a physical state. Mosul is on the verge of being liberated. The Battle for Raqqa still has a few months to run and the final battle, the Battle for Deir ez-Zur, has not yet begun. The defeat of Islamic State will not, however, end the turmoil in eastern Syria or western Iraq. It simply sets the stage for an even more complicated geopolitical minuet.

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