The most challenging part of the US-led coalition’s involvement in the Syrian conflict was supposed to be the military campaign to defeat ISIS’s so-called caliphate. Instead, now that ISIS has been defeated and the caliphate no longer exists, dealing with the many issues that have arisen in the aftermath of its demise is proving to be no less difficult.
For, as Syria’s bitter civil war nears its endgame, with regime forces attempting to defeat the last remaining pockets of rebel resistance in Idlib province, the country is now becoming a battlefield in a wider struggle between rival powers, one that could lead to significant changes to the global landscape.
At the heart of this powerplay lies Washington’s determination to ensure the protection of pro-Western groups, such as the predominantly Kurdish Syrian Democratic Forces (SDF), which did the lion’s share of the fighting against the caliphate. To this end, Washington is trying to set up a “buffer zone” that will afford protection to the Kurdish border region between Turkey and regime-controlled Syria.
The American initiative, though, is being challenged by Ankara, which remains deeply suspicious of any arrangement that allows the Kurds to run their own affairs, as well as by Bashar Al Assad's regime, which remains determined to reclaim control of the entire country.
Tensions over the Kurds' predicament came to the fore this week when Mark Esper, the new US defence secretary, issued a blunt warning against any attempt by Turkey to launch a military incursion against Turkish-held areas. He told Ankara that any such move would be "unacceptable", and that the US would resist any Turkish invasion of northern Syria.
Turkish President Recep Tayyip Erdogan has warned repeatedly that his country is preparing for a military offensive in Syria against the People’s Protection Units, the Kurdish militia known as the YPG, which has received US backing as the main Kurdish element in the SDF.
The prospect of a direct confrontation between the US and Turkey has been averted after the two sides agreed to establish a joint operations centre to coordinate the running of a buffer zone for the Kurds in north-eastern Syria.
Yet, significant differences remain about the size and administration of the zone, with the Turks continuing to insist that it should be 32 kilometres deep in order to address their security concerns, while the Americans believe it should be no larger than 12km. Nor has any agreement been reached on how security is to be maintained in the proposed area, which will also be used as a “peace corridor” to allow displaced Syrians to return to their country.
The US is opposed to Turkey having responsibility for the zone because of fears they will use their military presence to confront the Kurds. But Washington has made little progress with its diplomatic efforts to persuade European and other international partners to take on the mission – yet another shameful example of the Europeans trying to wash their hands of their involvement in the conflict.
The situation on the ground is further complicated by the double standards Turkey has demonstrated through its dealings with both Moscow and Washington in recent weeks.
Despite the Trump administration's anger over Ankara's recent deal with Moscow to buy S-400 anti-aircraft missile systems, which raises some serious questions about Turkey's continued membership of the Nato alliance, the US relies heavily on the use of Turkish military bases to continue prosecuting the campaign against ISIS remnants.
Add to this complicated picture the interests of countries like Iran, which aims to use its presence in Syria to increase its ability to confront Israel, and it is clear that post-caliphate Syria remains every bit as challenging as it was when ISIS was administering its barbaric regime.
The wrangling between Washington and Ankara over the administration of a Kurdish buffer zone also risks overshadowing another vital issue that needs urgent attention, namely what is to be done with the hundreds of foreign fighters that have been captured during the final assault on ISIS, the majority of whom are still being held in Kurdish-run detention camps.
An estimated 800 foreign fighters from countries like Britain, France, Germany and the Netherlands are currently being held by Kurdish forces. But despite urgent appeals from Washington for European governments to take responsibility for their citizens and bring them to trial in their home countries – which is how the US is dealing with captured American fighters – the Europeans are refusing to cooperate, effectively abandoning the fighters to a judicial no-man’s land.
American officials are seriously concerned that, if the issue is not resolved soon, it could result in many of the fighters being freed and returning to ISIS’s ranks. Such a possibility cannot be overlooked as the SDF have said they do not have the resources to keep the ISIS detainees indefinitely, and security officials have warned that ISIS is already in the process of regrouping in Syria and has an estimated $300 million to spend on launching a new wave of terror attacks.
Allowing ISIS to reform would be similar to what happened in Iraq a decade ago when, after the US-led coalition succeeded in defeating the Al Qaeda-led insurgency. It subsequently allowed Islamist militants to regroup, which ultimately resulted with the creation of the caliphate.
“We made this mistake in Iraq, and we must not make the same mistake again in Syria,” a senior US official told me recently.
The US administration is certainly losing patience with the Europeans’ disinclination to accept responsibility for dealing with the captured fighters, with President Donald Trump threatening last week to forcibly repatriate them to Europe unless there was a change of policy. All of which suggests that, while the war against the caliphate has been won, the struggle for post-conflict Syria is set to continue for some time to come.
Con Coughlin is the Daily Telegraph’s defence and foreign affairs editor