Aside from President Obama, none of the main players in Syria has an interest in rushing toward Raqqa, so they will likely focus on exploiting the various campaigns around Aleppo instead.

Despite the ongoing peace negotiations in Geneva, each camp in the Syria war is preparing for a general resumption of hostilities in the Aleppo area. In addition to the strategically important city itself, the Islamic State-occupied territory between Aleppo and the Euphrates is increasingly becoming a focal point, shifting attention away from the group's stronghold to the east and likely further delaying the Obama administration's goal of pushing IS out of its "capital" in Raqqa.

CONTINUED ENCIRCLEMENT

On February 27, a ceasefire temporarily halted the Russian- and Iranian-backed Syrian army campaign to encircle the rebel-held portions of Aleppo city. By that point, the army had already cut the road to the border town of Azaz with the cooperation of the Kurdish Democratic Union Party, or PYD (see PolicyWatch 2554, "The Battle of Aleppo Is the Center of the Syrian Chessboard"). That resulted in a hostile reaction from Turkey, which fired on the Kurdish militia to prevent it from taking Azaz city and the nearby Bab al-Salam crossing point. The Syrian army had also advanced against the al-Qaeda-affiliated rebel group Jabhat al-Nusra Front to the south of Aleppo and against Islamic State (IS) forces to the east, widening the perimeter around Kuweires military airport.

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Meanwhile, on the northeastern side of the IS enclave, the PYD seized Tishrin Dam and crossed the Euphrates in December but did not take the opportunity to press further and seize Manbij city. The group's main partner against IS, the United States, opposed any such offensive because it would anger Turkey, which had repeatedly warned the Kurds not to advance west of the river (see PolicyWatch 2542, "The Die Is Cast: The Kurds Cross the Euphrates").

Today, the Assad regime strategy in Aleppo is apparently focused on creating a double belt around the city in order to isolate the eastern neighborhoods held by Arab and Kurdish rebels, which are connected to the opposition stronghold in Idlib province and the western supply line from Turkey via the Castello road. To form the innermost part of this belt, army forces north of the city advanced to less than a kilometer from the Kurdish-held district of Sheikh Maqsoud by seizing Mallah on April 14, and they are preparing to push further south soon. As for the outer belt, recent troop movements indicate that a broader offensive is brewing west of the city, between Zahra and Khan al-Asal, which should complete the encirclement of all rebel forces in the Aleppo area. Eventually, in the absence of a political agreement, the army will likely try to isolate the entire Idlib province in a similar manner.

The regime's recent moves are in line with its broader counterinsurgency strategy, which involves cutting the opposition's supply lines from neighboring countries and separating rebels from civilians by forcing the latter to flee. This is why Bashar al-Assad has brazenly continued deplorable tactics in the middle of a supposed ceasefire and peace negotiation, from dropping dynamite barrels on eastern Aleppo to bombing markets in Maarat al-Numan and Kafr Nabl. Assad has been using the Geneva process simply to buy time, and he would abandon the talks with Russia's tacit consent the moment they threaten his hold on power. In any event, he will not substantially change his military strategy in the meantime.

WHAT NEXT FOR THE MANBIJ-AZAZ CORRIDOR?

Thus far, the Syrian portion of the U.S.-led campaign against IS has relied almost entirely on the Kurds, but this approach is not militarily sufficient to defeat the group. It is also politically problematic because the PYD wants to take Manbij before supporting any southern offensive against Raqqa. Manbij is an essential step toward connecting the two Kurdish enclaves on the border with Turkey, and the Kurds have already proven that they will turn to other patrons if Washington does not support them in this goal. In January-February, Russian air support helped the PYD seize several villages held by Arab rebels, and this close coordination could be repeated on a larger scale between Manbij and the Afrin enclave to the west, against rebels and IS alike.

Yet Turkey has proven equally determined to prevent this scenario. As mentioned previously, President Recep Tayyip Erdogan deployed artillery to shell PYD positions two months ago in order to protect Azaz. According to private conversations with officials and other individuals in Washington and Damascus, Ankara also permitted thousands of rebel fighters, including Jabhat al-Nusra elements, to cross Turkish territory from Idlib province to Azaz, preventing the rebel corridor from collapsing completely. These fighters were then used against IS forces east of Azaz -- Erdogan's way of taking the field before the PYD and Syrian army begin their own offensives in earnest, with the goal of showing Washington that Turkish-supported rebels can defeat the Islamic State without further PYD advances.

This strategy has had mixed results, however. The transferred rebel units made few territorial gains, and half of them were quickly retaken by IS, pushing 30,000 more refugees toward the Turkish border. Apart from its general interest in preventing enemy advances, the Islamic State is particularly keen on protecting the town of Dabiq near the western front. In radical jihadist eschatology, Dabiq is the location where Islamic and anti-Islamic forces will fight on Judgment Day, so the group is willing to engage in costly fighting there.

Indeed, the divorce between Turkey and IS now seems final -- in the past, Erdogan looked the other way when the group was receiving support through Turkish territory given its efforts against the Assad regime, but recent IS terrorist attacks in Turkish cities have ended any remaining tolerance. Erdogan also likely understands that it is better to support U.S. efforts against IS if he wants to influence President Obama's stance on the Kurdish question in Syria. According to a private conversation with a well-informed Turkey expert, Obama asked Erdogan not to oppose U.S.-Kurdish efforts to take Manbij during their March 31 meeting in Washington. The Turkish leader apparently rejected that request, demanding that the Arab tribes currently fighting alongside the PYD break off from the group and take Manbij on their own. Yet these Arab tribes do not have the military capability to do so. Moreover, unlike Raqqa, Manbij is home to a large Kurdish minority, so it makes tactical sense to involve some Kurdish forces in its conquest. From a political standpoint, though, that would represent a further step toward the creation of a Kurdish state in northern Syria.

BROKEN CEASEFIRE MEANS A RAQQA REPRIEVE?

The resumption of fighting west of Aleppo, in the Ghab Valley and north of the Alawite Mountains, left little doubt that the fragile February ceasefire was over for good. Although Jabhat al-Nusra was never formally involved in the agreement, it did generally respect the ceasefire up until the end of March. The group also depends on Turkish goodwill for much of its materiel support, so it is difficult to imagine that Nusra forces or allied units took the initiative on their own to trigger large-scale hostilities (see PolicyWatch 2579, "How to Prevent al-Qaeda from Seizing a Safe Zone in Northwestern Syria"). Rather, Ankara and perhaps Saudi Arabia seem to have ordered their local proxies to take action. The regime bombardments in Marat al-Numan and Kafr Nabl on April 19 threw oil on the fire, but they are not the real cause of the ceasefire's collapse. As mentioned previously, Turkey seemed eager to take action of its own as a way of preventing Assad and the PYD from moving quickly against IS in the north.

For their part, although Damascus, Moscow, and Iran never viewed the ceasefire as anything more than a temporary measure, the early resumption of fighting around Aleppo is not necessarily good news for the Syrian army. Regime forces had needed a break in the west so that they could focus on important goals in the south and east, such as reopening the road to Deir al-Zour, relieving the loyalist enclave that has been surrounded since year one, and buffering Homs and Damascus from IS raids. The recent victory over IS forces in Palmyra was the first step in that plan, but Deir al-Zour remains the principal goal because it is the key to regaining control of the Euphrates Valley and cutting Raqqa off from the Islamic State's holdings in Iraq. The fact that Assad's best general -- Suhail al-Hassan, nicknamed "the Tiger" -- is on the Deir al-Zour front reflects the town's importance to the regime's broader military strategy.

Yet with the exception of President Obama, none of the main players in the conflict is in a hurry to advance on Raqqa itself or oust the Islamic State from Syria. For Erdogan, the group remains the enemy of his enemies, so he continues to avoid full-scale Turkish participation in the anti-IS campaign. For Assad, the group is a perfect foil, giving Western governments another reason not to force him out of power. The pro-Assad coalition believes that the United States is unable or unwilling to destroy IS in Syria without his help. Finally, for the Kurds, fighting the Islamic State is the best means of uniting their enclaves in the north and building a state of their own.

Fabrice Balanche, an associate professor and research director at the University of Lyon 2, is a visiting fellow at The Washington Institute.