AP Photo

I came to Iraq three days after Saddam Hussein fled Baghdad. It was April 12, 2003. At the time, Iraqis bristled when asked if they were Sunni, Shiite or Kurd. It made no difference, they said, they were brothers. And, in the heady aftermath of the war, for a short while it almost seemed true. That mood seems to be upon the country again, and it is most welcome after the last six years of bloody murders between Shiites and Sunnis; between Arabs and Kurds; between Muslims and Christians.

Will it last? Or are Americans, as they have been in Kosovo and Bosnia and perhaps now in Afghanistan, turning away from the inconvenient realities of ethnic and religious differences, the depth of animosities, of struggles for power and territory? As the country’s attention turns east to...