After September 11, 2001, President George W. Bush's administration presented a national security agenda that held two key goals: the denial of safe havens to terrorist groups with international reach, and the prevention of terrorist groups from acquiring Weapons of Mass Destruction (WMD). In 2002, a terrorist group, Ansar al-Islam, operating out of a camp in Khurmal, northeast Iraq, was reportedly developing cyanide gas, toxic poisons, and ricin for potential use against Europe and the United States. The Joint Chiefs of Staff unanimously supported, and formally presented to the White House, a military operation to destroy the Ansar camp. This article, based on research and interviews with senior military and civilian officials, assesses four plausible explanations for why President Bush deferred attacking the only place in Iraq that was producing WMD, albeit in small quantities, before the 2003 war. It argues that President Bush made the mistake of bypassing the Khurmal operation, because of concerns that it could have disrupted plans to remove Saddam Hussein from power. In addition, the article assesses what lessons learned from the decision not to attack Khurmal could be applied to other non-uses of limited force.