Editor's Note: This is the final report in a three-part analysis of the controversial Ayman al-Zawahiri letter. The controversial letter from Ayman al-Zawahiri to Abu Musab al-Zarqawi — which we believe is authentic despite certain apparent discrepancies — not only provides insights into the inner workings of the global jihadist movement, but also suggests that it is fast reaching an impasse. As a result, the bulk of the movement will either continue to seek guidance and leadership from Osama bin Laden and Ayman al-Zawahiri or it will attempt to assume a more political face. Should politics prevail, al-Zarqawi's proven ability to lead successful attacks will catapult him into a leadership role — and make him a rival to his current brothers-in-arms. It is too early to say which way the pendulum will swing, but one is thing is certain: The jihadist ranks have begun to fracture.