Understanding Why Terrorist Operations Succeed or Fail

Abstract : Understanding why terrorist attacks succeed and fail is important for homeland security and counterterrorism planning. In examining past terrorist attacks, this understanding is necessary to discern why attackers sometimes are very successful and why sometimes even reasonably well-planned operations fall apart. Discerning ways to make attacks less likely to succeed is a central goal of efforts ranging from homeland security technology development to the direct military engagement of terrorist groups. Given the importance of the issue, many analysts have approached the problem from a variety of different directions. Success and failure in the context of terrorist attacks have been defined in different ways, from the strategic down to the tactical level. Many factors that make contributions to operations going well or poorly have been identified. But in our work focusing on security planning, we have found the results of many of these past analytic efforts difficult to apply. In part, this is because of the tactical focus of such planning, but it is also because of the absence of a unifying framework that brings together the range of factors that can influence the success and failure of terrorist operations in a practical and applicable way. Based on past research examining a variety of terrorist groups and security planning problems, we have developed just such a unifying framework. At the heart of our model lies our contention that the past success or failure of a terrorist operation -- or the likelihood that a future attack will succeed -- can be best understood by thinking about the match or mismatch between three key sets of characteristics: terrorist group capabilities and resource, the requirements of the operation it attempted or is planning to attempt, and the relevance and reliability of security countermeasures.