The nature of the relationship between al-Qaeda and Iran is one of the most contentious debates in the counterterrorism community, dividing analysts, policymakers and government officials. The stakes of establishing or disproving the relationship are considerable—meaningful state support is immensely useful to terrorist organizations, especially one being hunted by the U.S. government. Current analytic disagreements are not necessarily about whether al-Qaeda and Iran have a relationship; on that point, there is little room for doubt.