United States

It seems clear that Islamic State is raising the stakes, aware that the gruesome death of an American and the image of another one at the mercy of an executioner who is taunting a US president could invite retaliation – heavier air strikes at least. But the United States and other Western powers may now be diverting their attention away from the Sunni insurgents innorthern Iraq to what they are capable of doing overseas. The group can draw on hundreds if not thousands of foreigners with Western passports that can keep them below the radar, like the British-sounding man who appeared to have killed Foley, to carry out its threats.