From the Washington Post:
While Bartlett offered no specific window, the U.S. ambassador to Iraq, Zalmay Khalilzad, has put the time frame at six months. In an interview this week with Der Spiegel, a German magazine, Khalilzad said, “The next six months will be critical in terms of reining in the danger of civil war. If the government fails to achieve this, it will have lost its opportunity.”
He’s probably right, of course.