Assessing the Dynamic Terrorist Threat

The September 11, 2001 attacks on the World Trade Center and the Pentagon illustrate the difficulty of forecasting new and emerging trends in terrorism. Although U.S. intelligence and security communities were tracking the activities of al Qaeda long before that day, many analysts appear to have underestimated either the network's degree of hostility toward the United States or its ability to carry out a catastrophic attack. Planners and policymakers must prioritize U.S. counterterrorism activities amid a constantly evolving field of potential adversaries. They must not only grasp the current threats to U.S. security but must also understand how terrorist groups' motivations and capabilities will evolve in the future.

The U.S. Air Force asked RAND Project AIR FORCE (PAF) to assess the character and magnitude of terrorist threats against the United States. PAF researchers developed a "threat framework" to evaluate terrorist groups on the basis of their motivations and ability to threaten U.S. interests. They also analyzed how terrorist groups maintain their capabilities and adapt to external pressures such as counterterrorism. Key insights include the following:

• Three terrorist groups evidence both the motivation and the capability to attack the United States, thereby posing the greatest threat. Al Qaeda, Lebanese Hizballah, and the Revolutionary Armed Forces of Colombia demonstrate the highest degrees of both hostility toward the United States as well as the ability to carry out sophisticated attacks. Some highly capable groups, such as the Liberation Tigers of Tamil Eelam, do not pose a significant threat to the United States because they have not demonstrated high degrees of anti-U.S. sentiment. By the same token, groups such as Jemaah Islamiya have demonstrated a willingness to attack U.S. citizens overseas but are unable to carry out large-scale operations. U.S. policymakers can use this framework to sort out which groups merit significant concern and which do not.
• Terrorist groups require organizational and operational tools to sustain their activities. Organizational tools such as ideology, leadership, recruitment pools, and publicity are necessary to sustain the group's existence as a cohesive entity. Operational tools such as command and control, weapons, training, intelligence, and money allow terrorists to conduct successful attacks. Understanding these factors may help U.S. policymakers identify means of reducing a particular group's capabilities. For example, if the United States wants to completely dismantle a terrorist group over the long term, then counterterrorism activities should seek to dismantle a group's organizational tools. If the United States wants to prevent a particular attack or alleviate an immediate threat, then it should target a group's operational tools.
• Terrorist groups can adapt to pressures, but they are vulnerable when undergoing transition. Groups such as al Qaeda and Hizballah have shown the ability to evolve when faced with countermeasures by state authorities, changes in support from other states or militant groups, or shifts in popular support. However, terrorist groups in transition face difficult choices about their organizational structure, strategy, and tactics. Understanding the pressures at work on a group may help counterterrorism authorities apply measures that increase the chances of terrorists' making bad decisions.

U.S. policymakers can use these insights to track the development of terrorist groups over time and to plan counterterrorism measures that are most likely to weaken or destroy a particular group.