With new waves of civilians fleeing violence in Anbar there are now more internally displaced Iraqis, nearly three million, than there were at the height of the bloody sectarian fighting that followed the American invasion, when millions of Iraqis were able to flee to Syria. That door is closed because of that country’s own civil war. And now doors in Iraq are closing, too, worsening sectarian tensions as the Shiite authorities restrict where fleeing Sunnis can seek safety.