"In explaining the decision to invade Iraq and oust Saddam Hussein from power, the Administration asserted, among other justifications, that the regime of Saddam Hussein had a working relationship with the Al Qaeda organization. The Administration stated that the relationship dated to the early 1990s, and was based on a common interest in confronting the United States. […]. Critics maintain that subsequent research demonstrates that the relationship, if it existed, was not 'operational,' and that no hard data has come to light indicating the two entities conducted any joint terrorist attacks. […]. Another pillar of the Administration argument, which has applications for the current U.S. effort to stabilize Iraq, rested on reports of contacts between Baghdad and an Islamist Al Qaeda affiliate group, called Ansar al-Islam, based in northern Iraq in the late 1990s. Although the connections between Ansar al-Islam and Saddam Hussein's regime were subject to debate, the organization evolved into what is now known as Al Qaeda in Iraq (AQ-I). […]. AQ-I has been a numerically small but operationally major component of the Sunni Arab-led insurgency that frustrated U.S. efforts to stabilize Iraq. […]. There have been indications that AQ-I is attempting to conduct activities outside Iraq in a process that some describe as 'spillover' from Iraq into the broader Middle East. However, another interpretation is that the U.S.-led war in Iraq has stimulated radical activities outside Iraq that are sympathetic to Al Qaeda."
CRS Report for Congress, RL32217