The world of state sponsorship cannot be divided simply into good and evil. There are gradations of culpability, and a failure to act can be almost as damning as supporting the wrong side. For many terrorist groups, a state's tolerance of or passivity toward their activities is often as important to their success as any deliberate assistance they receive. Open and active state sponsorship of terrorism is blessedly rare, and it has decreased since the end of the Cold War. Yet this lack of open support does not necessarily diminish the important role that states play in fostering or hindering terrorism. At times, the greatest contribution a state can make to a terrorist's cause is to simply not act against it. A border not policed, a blind eye turned to fundraising, or even the toleration of recruitment all help terrorists build their organizations, conduct operations, and survive.

This passivity in the face of terrorism can be deadly. In conducting the September 11 attacks, al-Qa'ida recruited and raised money in Germany with relatively little interference, enjoyed financial support from many Saudis unobstructed by the government in Riyadh, planned operations in Malaysia, and sent operatives to America. None of these governments are “sponsors” of al-Qa'ida – indeed, several are bitter enemies – but their inaction proved as important as, if not more important, than the haven the group enjoyed in Afghanistan in enabling al-Qa'ida to conduct the attacks.