FOXNews.com - Rumsfeld: U.S. Won't Back Down in Iraq

Rumsfeld said he believes a recently intercepted letter, purportedly from a terrorist organizer connected to the Al Qaeda terror network, is authentic. The letter writer, believed to have been Abu Musab al-Zarqawi, wrote of efforts to cause a civil war between the two major Muslim sects, the long-dominant Sunnis and the majority Shiites.