Afghanistan would have been difficult enough without Iraq. Iraq made it impossible. The argument that had we just focused on Afghanistan we'd now be okay is persuasive, but it omits the fact that we weren't supposed to get involved in nation-building in Afghanistan.In my new book, I open with a quote from Donald Rumsfeld. In October 2001, he said of Afghanistan: "It's not a quagmire." Ten years later there are 150,000 Western troops there.