Tomorrow marks a major milestone in Iraq as the Iraqi Government takes responsibility for paying and integrating large numbers of the Sons of Iraq (SOI) - the former Sunni insurgents who began aligning themselves with the U.S. in 2006 and were one of the main reasons for the reduction in violence. There are still significant tension between the Shi'a dominated central government and the SOIs; and, if the government does not continue to pay these fighters or integrate enough of them into the security forces, it could spell trouble.