Naturally, this situation casts doubt upon the prospects for the long term success of the agreements. And in fact, earlier ceasefires have failed on multiple occasions, with Iran and its local proxy forces frequently taking a major share of the blame. Following the siege of Aleppo, for instance, Iran-backed forces halted civilians in the midst of their relocation and demanded the simultaneous relocation of Shiite partisans out of rebel-controlled territory. This speaks to the apparent Iranian effort to partition regional conflict zones along sectarian lines as the Islamic Republic angles to make itself the head of a “Shiite crescent” extending from Tehran to Beirut.

This ambition has also been cited as the essential reason for Tehran’s objection to the southern deconfliction zone, because it allows US-backed forces to become further entrenched there, and likely cuts off a planned Iranian route passing from Tehran through Iraq and Syria and into Lebanon, where the Iran-backed Shiite paramilitary Hezbollah is headquartered.

The development of this Shiite crescent has been driven in large part by Iran’s promotion of local Shiite paramilitaries in both Syria and Iraq. Hezbollah itself is among these, and the Syrian Civil War has apparently allowed it to develop a permanent foothold in the Golan Heights, just across the border from Israel. Meanwhile, other paramilitary organizations have been described as being significantly modeled after Hezbollah, meaning that to a great extent they are poised to be appendages of the Iranian regime in surrounding territory.

The further escalation of this situation is viewed as a threat by various Arab governments in the region, and of course also to Israel. The Canadian Press explains that the establishment of the southern deconfliction zone was made more imperative by growing concerns from the Jordanian and Israeli governments. One Jordanian official said that moves toward the development of a Shiite crescent would be considered a “super red line,” and he went on to also highlight concerns about the establishment of Iranian missile production inside Lebanon, and the ongoing link-up of Syrian and Iraqi forces that are backed by Iran.

Concerns abound about the growing influence and territorial reach of these sorts of forces. And those concerns are by no means limited to the Jordanians and Israelis. On Wednesday, The Iranian featured an interview with a spokesman for one such militia, centered in the Iraqi province of Kirkuk. And although that spokesman sought to downplay the extent of Iranian backing and influence, the interview repeatedly emphasized the concerns that have been voice by the Kurdish military and other groups involved in the fight against the Islamic State militants. Many of them do not wish the Shiite militia groups to participate in that fight, fearing potential consequences such as the promotion of Iranian candidates for local government positions and the permanent establishment of a paramilitary presence that answers directly to Iran.

The spokesman, Ali al-Husseini, denied that his militia takes orders directly from Iran, but he also proclaimed that the organization was “proud” to have Iranian backing, and he acknowledged that their loyalty was not restricted to the Iraqi government but also extended to the head of the Badr Organizations and other Shiite militia commanders, many of which are in turn under the direct influence of Tehran.

What’s more, in some cases these organizations fight alongside the Iranian Revolutionary Guard Corps or even under the command of IRGC officers. This fact was highlighted, for instance, by Ya Libnan on Tuesday, in an article detailing boastful comments made by Hezbollah leader Hassan Nasrallah regarding the extend of Iranian power and influence Syria and Iraq. As well as quoting Nasrallah as dismissing the significance of US-led coalition air strikes and crediting Iran with the victory of Islamic State forces at Mosul, the article also pointed out that Qassem Suleimani, the head of the IRGC Quds Force and “Nasrallah’s boss”, was reportedly at the head of the Shiite militants who fought IS in and around Mosul.

At the same time that this highlights some of the reasons behind international demand for a southern deconfliction zone in Syria, it also goes to show that the establishment of that zone may not be sufficient on its own to alleviate concerns about the development of an Iran-led Shiite crescent. Furthermore, whatever effectiveness is promised by that zone, it will only be realized to the extent that the agreement’s enforcement is successful. And with Iran’s history of breaking previous agreements, that remains much in doubt.