Events of historic consequence are occurring in Syria’s eastern desert and the Euphrates valley. Out of the countless events of the Syrian war so far, the...

Events of historic consequence are occurring in Syria’s eastern desert and the Euphrates valley. Out of the countless events of the Syrian war so far, the present moment may be the most important one in deciding the near geopolitical future of the Fertile Crescent.

Daesh—the so-called Islamic State—is falling. Chances are, it will remain an international network of terrorist organizations and guerrilla movements in the fashion of Al Qaeda, but will soon cease to exist as an entity with control over territories in Syria and Iraq. In its place will be a contest for who will inherit the key strategic areas after the demise of the group’s self-professed “Caliphate.”

Iran, assisted by Russia, is close to emerging victorious in this struggle and reaching its primary geostrategic goal of the last decade—creating a geographically contiguous sphere of influence encompassing the northern part of the Middle East.

An empire within reach

Iran has strong influence on the Iraqi government, while the Shia militias campaigning against Daesh in Iraq’s northwestern desert near the Syrian border are even more directly aligned with Iran.

In Lebanon, Tehran’s political clout is enormous through its relationship with Hezbollah, which answers directly to Iran and is militarily stronger than the Lebanese army. Syrian Pres. Bashar Al Assad’s regime was an Iranian ally before the war. Now it’s an Iranian satellite.

The only hurdle Tehran faces before it can unite all of these pieces into a single geopolitical space is lack of control over the Syrian-Iraqi border. If Iran overcomes this hurdle, it will dominate the enormous area between western Afghanistan and the Mediterranean Sea—a feat unaccomplished by Persian powers since the ancient empire destroyed by Alexander of Macedon, with only one brief exception in the 610-620s.

This historical observation does not exhaust the importance of Iran potentially controlling the land routes through Iraq and into Syria and Lebanon. Such a development would have profound security consequences. It would simplify Iran’s support for the Assad regime, likely making the Syrian rebels’ military position—already difficult—untenable.

Hezbollah would also secure a land link to Tehran. As a result, Iran would no longer need to rely on indirect routes for its arms shipments to this organization. The Islamic Revolutionary Guards Corps could simply load trucks in Iran and send them by road to the Israeli border with equipment and weapons—or even with troops, if the IRGC chooses to.

It is an easy prediction that an Israeli reaction to such a state of affairs will be vigorously negative.

Above—U.S.-backed rebels control the Tenef crossing in southeastern Syria, as regime troops dash toward the Euphrates valley in the east. Illustration via syria.liveuamap.com. At top—Iraqi Popular Mobilization Forces tanks in Fallujah. Mahmoud Hosseini photo via Wikimedia

Key roads

Apart from the territories that the Kurds control and do not intend to give up in anyone’s favor, there are two main roads that connect Iraq to Syria. One goes through the Tenef border crossing, close to Jordan. Another runs through the Euphrates valley—a thin thread of populated land with desert on both sides of it.

Iran needs to gain firm control over at least one of these two routes to construct its contiguous zone of dominance.

The United States has been working to prevent the Tenef crossing falling into the hands of Assad and Iranian-sponsored armed groups that operate in Syria. First, the United States, along with Jordan, supported rebel groups in the Tenef area which captured the crossing from Daesh in March 2016. U.S. and British special forces then established a base in Tenef.

Finally, during the last several weeks, the U.S. Air Force has conducted two air strikes targeting Iranian-sponsored forces that advanced on the base, and shot down two Iranian-made drones in the area. As long as the United States remains committed to controlling the Tenef crossing, it will be impossible for Iran and its Syrian ally to capture it. Regarding the Euphrates valley route, however, the situation is very different.

The portion of the Euphrates valley that crosses the Syrian-Iraqi border is in the hands of Daesh. But since Daesh is being crushed, that area will soon fall under someone else’s control. Recognizing the critical importance of the present moment, Iranian-sponsored forces launched a desperate offensive toward the Euphrates valley—see a recent video from the offensive embedded below—and appear to be close to capturing the border crossing.

Three prongs of advance

The Syrian regime is conducting its offensive toward the Euphrates border along three axes.

The northern one follows the Euphrates River itself, just south of Raqqa and the areas liberated from Daesh by the Syrian Kurds and Arabs—with American help—united under the Syrian Democratic Forces. The central axis of the offensive begins in Palmyra and is directed toward Deir ez-Zor, a regime city on the Euphrates presently besieged by Daesh.

When successful, the central offensive will relieve Assad’s garrison there, and then use Deir ez-Zor as a staging position for gaining control over the remaining valley.

Finally, Iranian-backed Syrian troops recently made a bold thrust across the desert, reaching the Iraqi border northeast of Tenef. This move cut off the rebels and the U.S. and British special forces in Tenef from Daesh-controlled territory, depriving them of using that fight as a reason to advance toward the Euphrates valley crossing.

This clever maneuver made the Iranian goal of gaining a permanent link from Iraq into Syria more attainable than ever since the start of the Syrian war .

A U.S. F-15E Strike Eagle over Iraq in December 2016. U.S. Air Force photo

America constrained

America has few options for preventing this link from becoming a reality. The SDF has already clashed with the regime offensive’s northern axis, as both keep capturing territory from Daesh in the same area. On June 18, a U.S. F/A-18 shot down a Syrian Su-22 jet that was bombing SDF positions. But the SDF is ill-suited to prevent Iranian domination of the Euphrates valley.

While the SDF includes Arab units, its core force are the Kurds—making it difficult for the group to advance deeper into ethnic Arab areas.

It is therefore unlikely that the SDF alone will fully cut even the northern axis of the offensive. Even if it did so, that would not be enough due to existence of the central Palmyra-Deir ez-Zor axis. The latter lies further south, where an SDF advance is very unlikely. It might be conceivable, but only in the case of a serious commitment of U.S. forces who would have to be prepared to engage against Iranian-backed Syrian troops.

So far, the United States has not indicated it will go down such a path.

Another option is for the Syrian rebels, supported by the United States and Jordan, to advance across the desert northeast of Tenef. Such an advance would reach the Daesh-held area of Al Bukamal almost directly at the crossing. Control over that area by U.S.-backed forces would block the Iranian land route from Iraq into Syria in a similar manner to Tenef.

In fact, the U.S.-supported rebels tried advancing on Al Bukamal in June 2016. But Daesh was still quiet formidable at that time, and neither the rebels’ preparedness nor the American support for the operation were sufficient. The jihadists defeated the rebels’ attempt.

Presently, the window for stopping an Iran-to-Syria land route is closing quickly. As noted above, Iranian-backed Syrian troops conducted a bold maneuver, blocking the U.S.-backed rebels and Western commandos from advancing northeast from Tenef. This means that if the rebels try to advance in that direction, they will have to engage Iranian-backed troops.

It appears highly unlikely that the rebels will be able to do so successfully without direct American participation.

The IRGC launches a Zolfaghar ballistic missile toward Syria on June 18, 2017. IRINN photo

Dilemma

All of this means that Washington has no options for preventing establishment of the Iranian land link across the northern Middle East that do not involve some kind of a direct conflict with the Syrian regime.

Such options would exist if, in the past, the United States had done more to secure the Euphrates border crossing in the Al Bukamal area by liberating it from Daesh. Now, however, the American leadership is in a very difficult position, because a direct fight with Assad’s forces means risking confrontation with both Iran and Russia.

The United States faces an unenviable dilemma. If it permits the establishment of an Iranian-controlled land link into Syria, the regime’s triumph in that country will become almost inevitable. Such a link would also greatly increase the risk of another war between Israel and Hezbollah. It is possible that Syria and Iran would be involved more directly in such a conflict than they were in the war of 2006.

Moreover, Iran’s domination over the northern part of the Middle East would further encourage its robust foreign strategy in other places, such as the Persian Gulf. In a number of future scenarios along these lines, the United States would be compelled to support its Middle Eastern allies and partners in a confrontation with Iran.

On the other hand, there is presently very little appetite in the White House, or in the United States generally, to risk conflict with Russia and Iran in Syria.

It remains to be seen how the United States might respond to the Iranian-backed advance on the Euphrates valley. Whatever the course of action or inaction—the potential for further conflict in the region will remain very high.