Ever since the Syrian rebels were overrun by al-Qaeda and other Islamist movements of a similar uncompromising hue, I have been warning that, rather than backing the rebels, the West’s interests would be far better served by doing everything in its power to halt the violence, even if it means the detestable regime of President Bashar al-Assad surviving. In the pragmatic world of realpolitik, better the devil you know than having a vital Arab state such as Syria succumb to the rule of Islamist fanatics. But ever since anti-government protests first erupted in Syria in the spring of 2011, Western leaders have generally eschewed this common-sense approach in favour of supporting the rebels.