“I saw this firsthand when I worked in the Obama campaign and in the summer of 2008 met with Hoshyar Zebari, the Iraqi foreign minister. When I asked him about the agreement to withdraw, he told me it was a non-negotiable demand. When I relayed this to Denis McDonough, who was on the campaign trail with Obama and eventually became his chief of staff, he was surprised and asked me if I was certain about what I heard. In 2009, while on a visit to Iraq, I brought this up with several Iraqi government officials in the parliament and the executive branch and received the same answer. Finally, in December 2011, when Iraqi prime minister Nouri al-Maliki came to Washington to finalize the deal, I and several others, including Obama’s first national-security adviser General David Jones and future Secretary of Defense Chuck Hagel, met with him. I asked him directly if there was anything President Obama could have done to keep the troops in Iraq. He essentially said that Bush made an agreement and the U.S. must stick to it. At the meeting, Jones said Obama was willing to leave 10,000 troops.”
https://www.yahoo.com/news/real-reasons-u-t-win-103057654.html