Well, my twopennies worth and no doubt I will be machine gunned.
Thousands or hundreds of thousands of Muslims on the streets of Jakarta, Karachi, Islamabad, Ürümqi, Harbin, Cairo, Tripoli, Lagos, etc etc wiould help but it ain't likely to happen. The solution must lie within fellow Sunnite countries or near Sunnites - and here I point the finger at Saudi Arabia to step forward and take action, politically or lead the military fight and pull in the likes of Turkey and Iran - who are also very concerned with IS, as has been reported.
A friend of mine was back from just north of Jeddah last weekend and said the place is going 'shitless' over what is happen, youngsters (and both sexes too) are being called up, security is being tightened up enormously so, and they are preparing at least to defend - but what is needed is for them to go onto the front foot - and that is where I would have Cameron, Obama and the rest pressing - a squeeze from Iran, Turkey and Saudi and where can they go, especially if Russia and its satellites were to oblige, the UK/US/French/Chinese navies etc standing off in the Gulf and Med......
The one question that the leaders need to address is what happens in the event of a vacuum, something that the idiot political priests in the form of Blair and Bush failed to address as to Iraq round 2.