There are enough countries already launching airstrikes – to the point where they risk acting at cross-purposes and endangering each other. What special extra element can the RAF add, other than trying to demonstrate Britain’s military prowess (to the UK itself, but primarily perhaps to the Americans)?
Even if the forces of Isis are attacked even more intensively from the air, the military consensus appears to be that they cannot be defeated without ground troops. Will western forces, in the end, be able to resist the calls for such an escalation? And what would the longer-term effect be anyway? The appeal of Isis lies not only in its military power, but in religion and ideology. That appeal will not be countered by western arms; it is more likely to be bolstered.
After more than two years, the central purpose of military intervention in Syria has still not been clarified. Everyone now insists they are fighting Isis, but the US, Jordan and others intervened at the start in support of those opposing President Assad. Turkey eventually joined in, and chose primarily to attack Kurdish PKK forces. Russia’s airstrikes have been intended to boost Assad as much as to push back Isis. Where will any UK airstrikes fit in? Whose war will we actually be fighting?