The savage advance of Sunni insurgents led by Isis has put the future of Iraq in doubt this week. The fighting threatens the entire region and exposes political weakness and duplicity As Iraq’s sectarian violence once more dominates the headlines, it is security that is uppermind in ­people’s thinking when they consider a response. Yet this is to repeat the errors of the US-led invasion of 2003. For to the extent that it was recognised at all as a political problem, Iraq was seen then as a political problem to be solved by military means.The easy triumph of the early post-9/11 intervention in Afghanistan encouraged the United States to use its superb military assets to reorder the Middle East, for so long the source of grievance. And in the then Prime Minister Tony Blair,