"It will require an enormous amount of diplomatic work from countries in [the] region and worldwide," he said. "The sad, unvarnished truth of the matter is that our all-volunteer force simply can't contain someone else's civil war. Our biggest threat in Iraq doesn't come from al Qaeda — it comes from being stuck in the middle of a civil war."
Batiste also said it would not suit U.S. interest if Iraq was dominated by another country in the region.
Batiste led the 1st Infantry Division in Iraq until 2005, when he grew disillusioned with the war and retired. He said the country needed a better plan for withdrawal than it had when it entered the war.
"This has to be done in a very disciplined way," Batiste said.
While he said a preponderance of troops needed to withdraw because the war had destroyed the all-volunteer military force, Batiste said some should remain to secure and protect.
"If there are extremist Iraqis operating, we would certainly go after them," he said, "but we don't need to leave 160,000 troops in Iraq."