"Despite real improvements, the Iraqi Security Forces (ISF)—particularly the Iraqi police—will be hard pressed in the next 12-18 months to execute significantly increased security responsibilities, and particularly to operate independently against Shia militias with success. Sectarian divisions erode the dependability of many units, many are hampered by personnel and equipment shortfalls, and a number of Iraqi units have refused to serve outside of the areas where they were recruited."To learn more about the readiness of Iraq's security forces I suggest you read these postings on training and equipping forces.
"Coalition capabilities, including force levels, resources, and operations, remain an essential stabilizing element in Iraq. If Coalition forces were withdrawn rapidly during the term of this Estimate, we judge that this almost certainly would lead to a significant increase in the scale and scope of sectarian conflict in Iraq, intensify Sunni resistance to the Iraqi Government, and have adverse consequences for national reconciliation.Matteo has speculated several times on the involvement of Iran in Iraq, suggesting that Iran is not a major supplier of weapons to Iraqi militias, despite the US administration's claims to the contrary. Read more here.
Iraq’s neighbors influence, and are influenced by, events within Iraq, but the involvement of these outside actors is not likely to be a major driver of violence or the prospects for stability because of the self-sustaining character of Iraq’s internal sectarian dynamics."
full report is available here: http://www.dni.gov/press_releases/20070202_release.pdf