An excerpt from, "Al Tanf garrison: America’s strategic baggage in the Middle East" By Daniel L. Magruder Jr, Brookings, November 20, 2020:
Al Tanf is a tiny outpost near the tri-border region in southeast Syria straddling the Baghdad-Damascus highway. There is a token U.S. military presence along with a partner force, the Maghawir al-Thawra (previously called the New Syrian Army). Originally, the area was held by ISIS, but was occupied by friendly forces in early 2016. In a deal brokered with the Russians, there was a 55-kilometer deconfliction zone circumscribed around the garrison, which is patrolled by Americans and their partners.
Currently, there are at least three justifications for sustaining the U.S. presence at Al Tanf: interdicting ISIS remnants, disrupting the Syrian economy and Iranian influence, and its potential for political leverage in negotiations.
An excerpt from, "Trump’s Air Strike on al-Tanf: No to the Shiite Crescent" By Hillel Frisch, BESA Center Perspectives Paper No. 483, June 1, 2017:
The two recent US air strikes on a Syrian convoy heading to the al-Tanf military base in the southern Syrian Desert a few miles from the Jordanian-Syrian border have major strategic importance. The attack signaled for the first time since the Syrian civil war broke out in 2011 that the US would not countenance the reemergence of the Iranian-controlled Shiite crescent that Iran had created through Teheran, Baghdad, Damascus, and Beirut after the US exited Iraq in 2010.
The US air strikes on a Syrian convoy heading to al-Tanf military base in the southern Syrian Desert a few miles from the Jordanian-Syrian border scarcely made any front pages in the world media. This was a major oversight. The strikes should have been a major headline, especially as they occurred prior to Trump’s visit to Saudi Arabia.
The attack signaled for the first time since the Syrian civil war broke out in the spring of 2011 that the US, under Trump, will not countenance the reemergence of the Iranian-controlled Shiite crescent that Iran had created to connect Teheran, Baghdad, Damascus, and Beirut. Iran had taken advantage of the US’s exit from Iraq in 2010 and the outbreak of the Syrian civil war a year later to establish that Shiite crescent.
Technically, the two air strikes were a minor affair. Two fighting F-15 jets struck a convoy of Syrian troops and unidentified pro-Syrian militia members, killing five to fifty of them as well as destroying several vehicles. The US justified the strike on military grounds. The convoy was likely to threaten elite US army troops advising Free Syrian Army-linked forces, who, together with YPG Kurdish forces, have pushed ISIS back to Raqqa, its last major stronghold in Syria.
According to the US army spokesperson, the strike hardly came as a surprise. The Syrians had long known of the 35-mile radius “deconfliction” zone around a former Syrian army base that US special troops use to train their local allies. Syrian forces were aware that they were forbidden to enter that zone.
The real goal behind the attack lies in the reason the Syrian convoy risked penetrating the area. The Syrians and their allies were obviously trying to link up with pro-Iranian militias operating against ISIS around Mosul, the last and crumbling stronghold of ISIS in Iraq. Syria and its Iranian patron reasoned that as ISIS was responsible for rupturing the Iranian-controlled Shiite crescent in 2014 when it captured Raqqa and Mosul and the vast space in between, the defeat of ISIS had to be a prelude to resurrecting the crescent.
President Trump obviously thought otherwise. Unlike his predecessor, who viewed Iran as part of the solution to lowering the flames in the Middle East, Trump sees Iran as very much part of the problem. That position that is in tandem with that of Saudi Arabia, the Gulf States, and Jordan (from where the F-15s might have taken off). All those states view Iran as the major threat by far to their national security.
There could be no better way to express the new American administration’s unity of purpose with its traditional Gulf allies than a military strike to show its commitment to containing the Iranian crescent threat. The timing of the strike was perfect – two days before the president and his entourage landed in Riyadh to sign multibillion-dollar armament deals between the US and Riyadh.
. . . Above all, the strike and its vast regional implications demonstrate that the containment and, possibly, the ultimate defeat of ISIS are hardly likely to enhance the prospects of achieving peace in the area. To the contrary, the rollback of ISIS is only going to intensify the conflict between the various militias on the ground, as well as their national and international sponsors.
Only the promotion – or thwarting – of an Iran-dominated Shiite and heterodox arc, with all its implications for the regional and international balance of power, can catapult a small patch of desert devoid of any natural resources, known hitherto only to local geographers, into an international flashpoint. Commit to memory the name and location of al-Tanf. It is liable to haunt the wider Middle East for years to come.
An excerpt from, "Contain, Enforce, and Engage: An Integrated U.S. Strategy to Address Iran’s Nuclear and Regional Challenges" Carnegie Endowment For International Peace, October 26, 2017:
Protection of Israel and Jordan has been one of the central rationales behind U.S. support for the Southern Front—a coalition of moderate fighters who control portions of southwest Syria. Keeping Iran-supported militias out of this area should be a readily achievable objective, as U.S. partners hold the upper hand in this part of Syria and simply keeping the status quo in place would be sufficient. The Trump administration has agreed to a ceasefire in southwest Syria with Russia and Jordan to address this concern. But while the U.S. administration appears committed to keeping Iranian forces off of Israel’s border, it is not yet clear whether the details of the de-escalation agreement will ensure that outcome. And Israel has expressed concerns that if Russian forces act as monitor of the agreement they will not stop Iranian encroachment into this area. The United States should prioritize this objective in its broader negotiation with Russia on Syria and if necessary be willing to place a number of U.S. forces into southwest Syria to oversee the implementation of a ceasefire and also provide intelligence, surveillance, and reconnaissance (ISR) capabilities to monitor implementation of the agreement.
The concept of an Iranian land bridge has received significant attention in the press and from regional analysts but is often misunderstood. Using land routes to transport a large number of Iranian forces or materiel 1,000 miles across some of the most treacherous terrain of the Middle East is impractical, especially when Iran already has air routes into Damascus and is helping Hezbollah build a domestic weapons production capability Lebanon. Iran’s real objective is to hold as many key lines of communication as possible within Syria and Iraq so that it can more easily move its forces including Hezbollah, other Shia militias, or the IRGC Quds Force within and between these territories; give itself maximum battlefield flexibility; and develop diversified supply routes.
The United States should limit Iranian flexibility and control of these lines of communication, though it must also recognize that this will be more difficult and less important than its top priority in keeping Iran out of the Golan Heights and Israel’s border areas. By maintaining forces at al-Tanf in Syria, the United States has cut off Iranian use of the southern (and most direct) route from Baghdad to Damascus. Because protecting this enclave comes with a significant U.S. resource commitment, especially in terms of air support, the United States should look for alternatives with partners that reduce this burden. In the north, the United States should be able to use its close alliance with Syrian Kurds to prevent Iranian shipments of weapons. The question will be at the border crossing between Anbar and Deir Ezzor Provinces. If American-supported forces are able to retake this territory from the Islamic State, they would cut off any options for Iran—though even if Iranian proxies hold it, it is highly inhospitable terrain for Shia militia groups.
Finally, it is important to recognize that such an approach will not fully prevent Iranian movement through this territory. Security vacuums plague eastern Syria and will continue to for years to come, and in that environment Iran will find opportunities to increase its influence and move materiel and personnel.
An excerpt from, "The Future of al-Tanf Garrison in Syria" By Grant Rumley and David Schenker, Washington Institute For Near East Policy, December 6, 2021:
At a Middle East Institute event in July 2020, U.S. Central Command chief Gen. Kenneth McKenzie Jr. noted that “our primary purpose for being in Syria is to conduct operations against [IS].” Yet his predecessor, Gen. Joseph Votel, hinted at broader goals while testifying to Congress in 2018: “[ATG] does have the derivative value of being along a principal line of access [and] communication that Iran and her proxies would like to exploit...So while that isn’t our mission, we do recognize the indirect impact that we have.”
In addition to impeding Iran’s ground line of communication with Hezbollah and the Assad regime, the U.S. presence at ATG has also proven useful to Israel’s “campaign between the wars,” which has reportedly included dozens of air missions against targets in Syria. Some of these operations have struck Syrian bases where Iran’s Islamic Revolutionary Guard Corps and/or their militia proxies were expanding their presence. In the past, these missions were usually conducted by flying over Lebanon, but two factors have made the ATG deconfliction zone the less risky, more appealing route for Israel: the reportedly higher concentration of air defense systems in west Syria and around Damascus, and the growing Israeli concern about Iran supplying more advanced capabilities to its proxies. The ATG route of attack enables Israeli forces to avoid Syrian early-warning radar systems oriented to the west/southwest. It is unclear whether Damascus would deploy air defense systems to the area around ATG if U.S. forces were no longer present there.
The garrison has served Jordanian interests as well. American troops and their MaT partners help secure the kingdom’s remote borders with Iraq and Syria against smuggling and potential infiltration by IS or Iranian militias. Although Jordan has warned of the terrorism threat posed by Rukban camp, Washington has helped reduce this danger by establishing checkpoints and supporting the U.S.-trained security personnel who patrol the Syrian side of the border. Indeed, after President Trump ordered all U.S. forces out of Syria in 2018, King Abdullah II personally lobbied the administration to remain at ATG.