“It’s normal for a country to have control over all its territory,” a senior officer from the operations room of forces allied with the Syrian government told Al-Monitor on the condition of anonymity. “The Syrian army and [its] allies’ control over the Syrian border is logical and legal, and it’s laughable to listen to calls asking an army of a sovereign state to stay away from its borders.”

The Tehran-Beirut route is a symbolic connection, one that announces that the Iran-led resistance axis is intact, as it was before the eruption of the Syrian revolution in 2011 and IS’ capture of Mosul in June 2014. That said, from the Iranian point of view, the regional stage is now different.

A road link from Tehran to Beirut has been secured by Iranian-led Iraqi, Syrian and Lebanese forces. This means, according to some analysts, that Iran is now capable of supplying its main allies in Lebanon and Syria with weapons and rockets across a 1,100-mile-plus land route. This might, however, be an overstatement or a bit of hyperventilating analysis, given that in the past Israeli fighter jets have on several occasions hit alleged arm supplies near and around Damascus. A longer route, mainly through a no man's land in remote areas of Iraq, is likely to be vulnerable to hits by the Israeli or US air forces, not to mention possible attacks by insurgents, including IS.

Indeed, the regional confrontation and the intersection of interests suggest that the Sykes-Picot borders are practically vanishing in accordance with the interests of regional alliances. In other words, central governments are shifting their focus from national borders in consideration of the interests of the wider axis to which they belong. One manifestation of this was reflected in the celebratory mood of media supporting the so-called resistance axis as its forces arrived at a Syrian-Iraqi border crossing June 9, with reported contact made between the Popular Mobilization Units (PMUs) advancing from Iraq and allied forces from Syria, under the direct supervision of the Iranian Quds Force commander, Maj. Gen. Qasem Soleimani .

The war for the Syrian Desert is in fact a war for the heart of the Middle East. The Iranian-led coalition in Syria is racing against the US-backed forces there, as both seek to defeat the Islamic State (IS), the group that has shaped the face of the region for the last four years. It is a war in the desert to draw a line in the sand, some might say, or a war to draw a line across borders and connect four capitals : Tehran, Baghdad, Damascus and Beirut. Hence the battle is between two different regional and international agendas, with each side viewing the other as the real threat after the defeat of IS in Iraq’s Mosul and Syria’s Raqqa .

The senior officer added, “The US steps and measures on the borders weren’t surprising to us. We’ve been observing [the Americans'] moves in several areas in Syria, and to be realistic, given the number of troops they have on the ground, they are not likely to get involved in direct confrontations, but rather strikes from the air or via artillery.”

From the perspective of Syria's allies, he said, “The Americans were depending on local militias whom they trained to execute their agenda, [by] mainly creating [zones in] isolated areas and belts around Syria [where they can operate]. Yet it was clear [that] they bet on the wrong people. The US-backed forces weren’t up to the battle with our forces. They don’t have our experience nor do they have our determination and persistence.”

The advance in Syria toward the Syria-Iraq border was concomitant with progress toward the same border by the PMU in Iraq, led by Abu Mahdi al-Muhandis, who announced on June 10 that his forces had reached the frontier and “liberated 4,200 square kilometers [1,622 square miles] and 142 villages.” Of note, however, his forces have no intention of entering Syrian territory.

A PMU source who spoke with Al-Monitor on the condition of anonymity said that all recent steps along both sides of the border had been coordinated in an attempt to send a clear message: “No threats, no hurdles, no superpowers can defy the will of the peoples of Syria and Iraq, who are determined to dispatch IS and its allies from the two countries.” The source added that there had been many attempts on both sides of the border to stop the advance, including airstrikes and messages sent through friendly intermediaries. “All were in vain,” he noted. “Our forces knew what to do, where to be, and they finally accomplished the mission.”

On June 6, a US airstrike on a position held by the Syrian army in Tanf, near the intersection of the borders of Iraq, Syria and Jordan, was clearly aimed at drawing a bold line delineating respective areas of control. The strike took place around 35 miles from the US base in the region and signaled that the United States would not tolerate advances toward its facilities from forces allied with the Syrian government.

“We were always under the sight of the American drones, and we knew that,” the senior officer from the operations room told Al-Monitor. He went on to note that this approach did not stop the allied advance, stating, “The issue of reaching the Iraqi border is now behind us. They failed, and now the Syrian government’s objective is to extend its area of control on the borders. From a military point of view, if they want to stop us, they need ground forces — and they know well that they lack such forces.”

What about the "Shiite crescent"? Al-Monitor asked the senior officer whether the emerging realities on the ground are the very "crescent" many have been warning of and that Iran and its allies have always denied pursuing.

“Our fight and struggle alongside the Syrian government was never for sectarian objectives,” said the senior officer. “We are going to fight alongside any country facing such criminal and terrorist enemies. We care for Muslims, all Muslims, as we care for Christians. And this war proved that clearly, and this is why we are fighting beside our brothers in Palestine. We never saw them from the sick sectarian view, rather from the view of brotherhood and lifting the oppression they face by Israel, which today is the main regional ally of those backing the terrorists in Syria and Iraq.”