As the military offensive in Mosul intensifies and plans are drawn up for an assault on Raqqa, the forces opposing the Islamic State of Iraq and al-Sham (ISIS) must consider the political implications of tactical engagement, specifically, who will assume control once the terrorist group is defeated?

“When we talk about ISIS and the day after, filling the void is going to be the key factor for defeating ISIS,” said Hassan Hassan, a senior resident fellow at the Tahrir Institute for Middle East Policy. He said, “ISIS as a government body has to be weighed against concern that if you expel ISIS, it will open a new conflict in Syria.”

“I don’t think Syria is ready for the demise of ISIS yet,” he added, but in Iraq “there is cause for optimism.”

On October 17, Iraqi forces and a US-led coalition began the battle to retake Mosul, the largest city captured by ISIS. Iraqi government troops entered Mosul on November 1 to begin the next stage of urban combat to retake the city. However, the fight to regain control of Mosul could take months.

There is an additional operation in place to put pressure on ISIS in Raqqa, the terrorist group’s de facto capital in Syria. While Turkey wants the offensive on Raqqa to start after the battle for Mosul, the United States has called for an earlier start out of concern that ISIS is using Raqqa to plan an attack on the West.

Ultimately, its retreat in Mosul, in conjunction with territorial losses in Syria and pressure in Raqqa, signals the potential military degradation of ISIS.

Hassan joined Jessica Lewis McFate, director of tradecraft and innovation at the Institute for the Study of War; and Howard J. Shatz, a senior economist at RAND Corporation, at the Atlantic Council on November 2 to discuss the future of ISIS and the Middle East at large. Aaron Stein, resident senior fellow with the Atlantic Council’s Rafik Hariri Center for the Middle East, moderated the discussion.

According to Stein, “ISIS should not be thought of simply…as a boots on the ground, military force.” The group has demonstrable bureaucracy and influence in the region.

This fact must be considered when creating a strategy to defeat ISIS, particularly in a city like Mosul, which has long been a strategic location for ISIS, according to Shatz.

Stein said that “the battle itself seems, from a military standpoint, rather straightforward. The difficult part is the road that leads out.”

The fight against ISIS has reached a point where politics matter more than a military challenge, according to Hassan. Consequently, Mosul poses a greater challenge “because it is a political flashpoint,” due to the large number of stakeholders in the conflict.

The battle for control of Mosul is waged by a coalition composed of Iraqi government forces, US troops, Kurdish Peshmerga fighters, and Turkish forces. The coalition is threatened by ethnic, sectarian, and geopolitical points of contention, according to Hassan. However, he said, “the Americans have stitched fault lines, for now.”

McFate said that, “the longer the battle for Mosul goes, the more vulnerable the coalition becomes.”

“There’s grounds for hope in Iraq,” said Shatz, but “the international community should remain in the governance aspect. This is not just a counterterrorism exercise.” Ultimately, he added, “this is just policing and politics.”

In Syria, however, the Arab-Kurdish dynamic complicates the prospective Raqqa assault, said McFate. “The movements of tactical engagement can stoke regional volatility,” she added.

According to Hassan, Washington puts forth a strategy to eliminate ISIS first, and clean up the political mess later.

At the Atlantic Council on October 27, Anne W. Patterson, assistant secretary in the State Department’s Bureau of Near Eastern Affairs, said “some of the violence is going to get worse before it gets better, but we have to focus on the defeat of ISIS first.”

Since the Obama administration is “running out of time, they are becoming more unequivocal about who is going to go [to Raqqa]. They want the Kurds to go there,” said Hassan. However, he said that the international community underestimates the fear and suspicion of Kurdish forces throughout Syria. “There is a perception that [the Kurds] want to dominate northern Syria,” he said.

Hassan said that if the Kurds are involved in the assault on Raqqa and ISIS is driven out, the tension between Kurdish and Arab Syrians will create a power vacuum that may be filled by other extremist groups in Aleppo and Idlib. Ultimately, the key dilemma faced by opposition forces is whether to delay the assault on Raqqa until a suitable political solution can be reached, giving ISIS time to dig in, or rush in with Kurdish forces, leaving open the potential for further political conflict.

The situation is politically and ethnically problematic, said Stein, but these concerns are falling by the wayside in the desire to oust ISIS.

Shatz said, “with the Islamic State, it’s always a good idea to take territory from them, but it’s always a good idea to do it right.” He said territorial gains occur in two phases: liberating and holding. While the Kurdish forces are in the best place militarily to liberate Raqqa, “they are not in the best place to do the holding,” according to Shatz. “The hold force is perhaps the key element of the campaign such that getting to claim a victory tactically against ISIS…is going to stick to the tune of ISIS not having a chance to come back,” said McFate.

Ultimately, “all of the threads of the disparate war inside Syria can come together with any means of escalations…but more importantly, on the ethnic cleavages that ISIS preys upon, you now have a race between Kurds and Turks,” according to Stein.

Turkey’s involvement in the conflicts in both Mosul and Syria and Turkish President Recep Tayyip Erdoğan’s mistrust of Kurdish forces have strained relations within the coalitions against ISIS. Turkey, a NATO ally of the United States, continues to fight against Syrian Kurds, a group backed by the United States in the fight against ISIS and Syrian President Bashar Assad’s regime, thereby complicating the prospect for a united coalition to take Raqqa.

However, the fight against ISIS has united the opposition forces against a common enemy. “ISIS is the stabilizing force at the moment,” Stein said.

McFate called for US consideration of all parties involved in the fight against ISIS. Currently, the rebels are working with Jabhat Fateh al-Sham [Front for the Conquest of Syria/the Levant], formerly known as Jabhat al-Nusra or the Nusra Front. The group, which was once affiliated with al Qaeda, is designated a terrorist organization by the United States. It could be involved in the push to take Raqqa.

According to McFate, to have an al Qaeda group involved in taking Raqqa is to enable that group. “Our [US] anti-ISIS policy does not address al Qaeda. If it does not block al Qaeda, it enables al Qaeda,” she said.

However, “no matter how bad or how complicated that situation looks, it can always get worse, and it is getting worse because we are standing back and admiring that problem instead of acting,” McFate said.

Shatz said “there is a strong argument for greater international involvement in the war to the extent that it can bring stability to parts of Syria.” Yet, according to Stein, US engagement must be predicated on an understanding of the many forces at work in the Syrian conflict.

Rachel Ansley is an editorial assistant at the Atlantic Council.

Image: (from left) Aaron Stein, a resident senior fellow with the Atlantic Council's Rafik Hariri Center for the Middle East, moderated a discussion with Hassan Hassan, a senior resident fellow at the Tahrir Institute for Middle East Policy; Jessica Lewis McFate, director of tradecraft and innovation at the Institute for the Study of War; and Howard J. Shatz, a senior economist at RAND Corporation. (Atlantic Council)