Gen. Lloyd Austin (left), the top U.S. commander in Iraq, looks on as Vice President Joseph R. Biden Jr. (right) shakes hands with the James Jeffrey, the U.S. ambassador to Iraq, upon Mr. Biden's arrival in Baghdad on Tuesday, Nov. 29, 2011. (AP Photo/Khalid Mohammed)

Photo by: Khalid Mohammed

Gen. Lloyd Austin (left), the top U.S. commander in Iraq, looks on as Vice President Joseph R. Biden Jr. (right) shakes hands with the James Jeffrey, the U.S. ambassador to Iraq, upon Mr. Biden's arrival in Baghdad on Tuesday, Nov. 29, 2011. (AP Photo/Khalid Mohammed)