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 organisation. The Administration assessed that the relationship dated to the early 1990s, and was based on a common interest in confronting the United States. The Administration assertions were derived from U.S. intelligence showing a pattern of contacts with Al Qaeda when its key founder, Osama bin Laden, was based in Sudan in the early to mid-1990s and continuing after he relocated to Afghanistan in 1996. 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. Some major hallmarks of an operational relationship were absent, and several experts outside and within the U.S. government believe that contacts between Iraq and Al Qaeda were sporadic, unclear, or subject to alternate explanations. 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 organisation 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 stabilise Iraq. Since mid-2007, in part facilitated by combat conducted by additional U.S. forces sent to Iraq as part of a "troop surge", the U.S. military has exploited differences between AQ-I and Iraqi Sunni political, tribal, and insurgent leaders to virtually expel AQ-I from many of its sanctuaries particularly in Baghdad and in Anbar Province. U.S. officials assess AQ-I to be weakened almost to the point of outright defeat in Iraq, although they say it remains lethal and has the potential to revive in Iraq. Attacks continue, primarily in north-central Iraq, that bear the hallmarks of AQ-I tactics, and U.S. and Iraqi forces continue to conduct offensives targeting suspected AQ-I leaders and hideouts. As of mid-2008, there are indications that AQ-I leaders are relocating from Iraq to join Al Qaeda leaders believed to be in remote areas of Pakistan, near the Afghanistan border. That perception, if accurate, could suggest that AQ-I now perceives Afghanistan as more fertile ground than is Iraq to attack U.S. forces. The relocation of AQ-I leaders to Pakistan could also accelerate the perceived strengthening of the central Al Qaeda organisation.