Could Isis caliphate dreams in Syria reemerge?

Since his resignation as US defence secretary, Jim Mattis has made a few forays into the public limelight, written a book but has generally stayed out of the political muckraking going on in Washington. But in his latest appearance on US TV the former four-star Marine Corps general has made a comment which chilled me to the bones. He warned that the Trump administration's policy of pulling American special operations troops back from northern Syria would inevitably lead to the rise-again of Isis. He is not the only one warning of this possibility but if General Mattis says it I have to believe it is probably true. After all those years of tempestuous fighting in which Isis was effectively crushed and driven from their occupied territory, it would be the gravest and historically most shameful outcome if decisions by the Trump administration allowed Isis to return. They have never gone away of course, there are still thousands of them with their hateful ideology around the world, and at least 11,000 in prisons in northern Syria. But the attritional warfare waged against Isis by the Kurdish-majority Syrian Democratic Forces (SDF) backed by massive airpower and artillery power and special forces support from the US and dozens of other members of the anti-Isis coalition including the UK (the SAS have been at the heart of the battles) DID defeat Isis. They were scourged from the towns and cities they had occupied. Now the Isis leaders who are left must be looking to exploit the new chaos in northern Syria. Chaos is what they love, what all terrorists and insurgents love. Anarchy is eminently exploitable. Especially for the Isis fighters who are currently holed up in several prisons guarded by the SDF. The SDF are now turning their backs on Isis and confronting the Turkish troops who are trying to seize the towns which they had controlled ever since liberating them from their Isis occupiers. With the number of SDF guards around to keep the Isis prisoners in their jails dwindling by the day, there is a danger there could be a mass breakout. Then General Mattis's warning of a resurgence of Isis could really come to pass. This is a frightening prospect and I sincerely hope that the new chairman of the US Joint Chiefs, General Mark Milley, is warning Trump over and over again of the dangers of pulling all US troops out of Syria. If all the US troops leave - the 1,000 there are still working with the SDF - the SDF will give up their role as guardians of Isis prisoners. Trump has told Turkey that it will have to take over the role if President Erdogan succeeds in setting up his 30-kilometre-deep security zone in northern Syria. But Turkey has gone into northern Syria to keep Kurdish militias further back from the border, not to guard prisons holding thousands of Isis fighters. I fear Isis is waiting for that moment when it will relaunch its terror campaign.