Four quite different commentaries found today; two British and two American.

'The real threat from the Islamic State is to Muslims, not the west' by Sonny Handal. As the title implies he is worried:
In many ways it is perhaps the worst development in recent Muslim history since 9/11. There are two reasons for this: First, it is likely to cause even greater unrest in countries where Muslims aren't a majority, and second, the Islamic State group could tear apart the Middle East and cause further unrest for generations.
I have long argued that strategically it is important to keep India's Muslims in view, so this passage is not good news:
India, which has the world's second-largest Muslim population, is especially in shock after Islamic State sympathisers have turned up from Kashmir in the north to Tamil Nadu in the south. There is not one recorded instance of an Indian Muslim having fought for al-Qaeda, but already four are suspected of having joined the group.
Link:http://www.aljazeera.com/indepth/opi...357532975.html

Majid Nawaz, of the Quilliam Foundation, ex-radical, makes a good contribution on what ISIS means and its methods. His advocated response is wishful thinking:http://warontherocks.com/2014/08/wha...-east-needs/#_

Paul Pillar I expect is known to American readers anyway an ex-CIA analyst and writes in 'National Interest':http://nationalinterest.org/blog/pau...spective-11150

It is very much IMHO a plea to recognise lessons learnt and ends with:
In that regard we cannot remind ourselves often enough—especially because this fact seems to have been forgotten amid the current discussion of ISIS—that ISIS itself was born as a direct result of the United States going after a different monster in Iraq.
The last article, the shortest, is a braoder outlook:
We’re caught in a revenge cycle with a death cult, and it’s redefining modern warfare.
Link:http://www.washingtonpost.com/postev...ighting-a-war/