This development was not unexpected but it is significant on three levels. The first is that it is not just the US alone, but includes participation in one form or another from Sunni Arab states who represent the moderate interpretation of Islam supported by the vast majority of their faith. That is the overt coalition. But the covert coalition is much more interesting and in a global sense hugely more important. Russia and Iran are not objecting and neither is Syria, having been informed in advance; a courtesy which brought it on board. It is critical that Ban Ki Moon has nodded it through the UN on the grounds that Syria is no longer in control of the territory attacked. This all represents a complex web of diplomacy and statecraft of a quality not seen for a long time. It is important that the small time politicians who have not a clue what is going on and demand a meeting of the Security Council be ignored. That would require everybody to take up entrenched positions including a Russian veto.
The next question is ground troops, because however much pounding from the air you do (remember Viet Nam and the B 52 raids on Hanoi), unless you follow up the gaps opened up from the air on the ground, no long term advantage is gained. There are only three ground forces in the region capable of doing this and then only just. The Assad Syrian Army, the Kurdish Peshmerga and the Shia led Iraqi Army and its associated Shia militias. The Iraqi contingent is the weakest.
What has to be done is to fully equip all these forces with the latest weapons and in addition train up the Iraqis. Russia and Iran will keep Assad’s army fighting fit, the West generally can equip the very well organised and led Peshmerga and Iraq will be, as it is already, a combined effort of Iran, Russia and the US. This is an altogether new grouping of powers which flies in the face of what people have come to know as the line up of goodies and baddies.That is why it stands a much better chance of working. It will not defeat IS but it will neuter it to the point where moderate Sunnis will have a chance to shrivel its perverted ideas and regain lost territory. That will require the abandonment of the Sykes Picot map and the re-drawing of boundaries.
The UK is about to join the air assault, having gone through a delicate dance of diplomatic veils to make sure its Parliament says yes. Commentators, especially the much more aggressive British contingent, so unlike the deferential style in the US, are trying to tease out an admission that western ground troops will in the end be needed. Apart from the fact that public opinion on both sides of the Atlantic is dead against that, any such move would be a disaster and play right into the hands of IS who daily prays with all its might for exactly that to happen.
If ever such thoughts cross the minds of politicians they must add this to the mix. A fighting force that regained some ground would merely trigger another insurgency. To do the job you would need an army of occupation for the entire area of Syria, Iraq, Libya and maybe Lebanon. You are looking at up to three million men and women together with a Marshal style plan for civic and economic regeneration. It would last at least twenty years and would require the re-introduction of some form of conscription in the participating powers. Any western politician who proposes it would be toast and any general who argues it could be done with less, is of the kind who wins battles and loses wars.