Isis has hostile forces in every direction. It will face resistance from anti-Isis Syrian rebels in the west, the hostility of Kurds in the north, and, eventually, a counter-offensive from government forces to the south. Even if the government collapses – and we are a long way from that – then Iraq’s Shia majority will not accept a permanent jihadist state on their northern flank, let alone allow Isis to stroll into Baghdad. Saddam slaughtered Shias in 1991, and Isis has been slaughtering Shias for over a decade. The Shias have had quite enough, thank you.