It has been clear for several years that there are no good options in Syria. The Western invasion and occupation of Iraq and the bloody-mindedness of its post-occupation governments created the conditions for the emergence of Islamic State. Syria itself, or its remnants, is led by a mass murderer who has turned the Arab Spring into sectarian bloodshed on a population-wide scale. And the entire region is riven by proxy conflicts involving the US, Russia, Iran and the Gulf theocracies (which have provided vast amounts of funding to IS), while Turkey’s agenda has been driven more by its desire to crush Kurdish communities than to halt IS.

Any “solutions” will, accordingly, be difficult and of the “least worst” variety. The idea of allowing Assad to remain in power is gut-churning. Allowing the extension of Iranian influence in the region is a recipe for continuing sectarian instability. But with IS or IS-linked terrorist attacks on Russia, Hezbollah in Lebanon and now France, there is a clear international community of interest in helping establish a stable Syrian government that can in turn defeat IS and provide the basis for millions of Syrian refugees to return to what is left of their homes. (At the same time, Turkey must ensure its border is no longer a convenient transit point for foreign fighters, and the flow of cash to IS from our alleged allies in the Gulf states must be shut down.)

Achieving this will require some deeply unpalatable choices for more or less every participant in the process. But the alternative — massive foreign military intervention and occupation — has not merely been tried before and failed, it has delivered exactly the nightmare we are now facing.