The Al-Zawahiri Letter and the Coming Jihadist Fracture

An image grab taken from Al-Jazeera television on June 23, 2006, shows footage of al Qaeda's Ayman al-Zawahiri vowing to avenge the death of Abu Musab al-Zarqawi, who was killed in a U.S. air raid June 7. During al-Zarqawi's life, the two did not always see eye to eye.