The recent violence in Iraq stems from the recent election in March where the incumbent Prime Minister al-Maliki's political party lost 91 seats in the parliament. When these new lawmakers are seated, former Prime Minister Ayad Allawi will once again be elected as Prime Minister.
The current violence in Iraq is not directed at the U.S. troops there. It is politically driven. As noted by the British paper, The Gaurdian:
http://www.guardian.co.uk/world/2010/may/12/iraq-us-troop-withdrawal-delayThe latest bomb highlights how sectarian tensions are rising, as al-Qaida fighters in Iraq and affiliated Sunni extremists have mounted bombing campaigns and assassinations around the country.
The violence is seen as an attempt to intimidate all sides of the political spectrum and press home the message to the departing US forces that militancy remains a formidable foe.
Why is this important? Al-Qaida is working with Sunni extremists and politics in Iraq is largely based in religious divisions. While both al-Maliki and Allawi are Shia, Maliki solidified support from the Shia bloc and excluded Allawi, who as a result, turned to the Sunnis to gain power as a cross-sectarian candidate.
Why does this matter a hill-o-beans to the U.S. and why should it cause a delay in our withdraw? After all, U.S forces are largely confined to their bases and U.S. patrols are greatly reduced.
As noted from the article:
Earlier this week, Allawi warned that the departing US troops had an obligation enshrined in the security agreement and at the United Nations security council to safeguard Iraq's democratic process. He warned of catastrophic consequences if the occupation ended with Iraq still politically unstable.
That is, the U.S. has a binding obligation via the U.N. Security council to ensure the transition from al-Maliki to Allawi is made once the new lawmakers are seated. And Allawi is going to hold us to that obligation.