Second, Daesh is more vulnerable now for specifically military reasons. An aggregation (admittedly ramshackle) of Syrian-Arab and Kurdish forces has now succeeded in dominating the northern approaches to Raqqa. While these forces are supported by an unusual combination of actors – some by Russian president Vladimir Putin (pursuing malicious interests), some by the U.S. and Sunni Arab nations, and some by both — they collectively pose a potent threat to Daesh.
Raqqa, like Mosul, is compressed against the Euphrates River. Daesh would therefore face three choices in a battle for the city: surrender; run south into the desert (and face aerial obliteration); or face annihilation in separated blocks of the city (in a face-to-face, man-to-man urban battle). In short, the military situation favors attack. (The first factor, the discontent within Raqqa, is linked to this military factor: As the regional analyst known as “Beyond the Levant” noted to me, disgust for Daesh in Raqqa means that the population might even accept Kurdish forces.
Third, retaking Raqqa now would amount to a vital and serious strategic recognition of the broader regional politics at play in Iraq and Syria. Iran’s grand strategy is now to bring Prime Minister Abadi of Iraq under dominion. A victory over Daesh in Syrian Raqqa would also offer much-needed credibility to Abadi in Baghdad.