The unprecedented attacks on 9/11 underscored the importance of an overall strategy for homeland security that not only coordinates agencies’ efforts to prevent terrorist attacks, but also takes decisive actions to promote recovery following an attack. The magnitude of the 9/11 incidents, with approximately 3,000 deaths and over $80 billion in property and earning losses (Kunreuther and Michel-Kerjan, 2004a, 2004b), indicates that terrorism poses a significant risk. On 11 March 2004 (henceforth, 3/11), Madrid’s commuter train bombings again emphasized the vulnerability of industrial countries to terrorist events. More recently, this ever-present risk of catastrophic terrorist events was underscored by the failed attempt to bomb Northwest Airlines flight 253 on approach to Detroit on 25 December 2009 and by the suicide bombings on the Moscow subway on 29 March 2010. As terrorists seek in the future to outdo the carnage of 9/11, 3/11, and other catastrophic events, they may eventually resort to the use of weapons of mass destruction (WMD) (see Chapter 12). Thus, preventive measures by the authorities must address a wide range of possible attack scenarios, including standard terrorist attacks and those involving biological and chemical agents. By the same token, plans must be in place to respond to all possible attack scenarios. The digital age and the complexity of modern-day society provide terrorists with the opportunity to cause mass disruptions in communication, energy supply lines, or transportation. Actions to safeguard against attacks to society’s transportation networks involve a trade-off between safety and the free flow of passengers. Ensuring that almost no attacks will occur may slow passenger transit – say, in subway systems – due to long delays at entry points.

In order to have effective homeland security, component agencies must act in unison not only at the same jurisdictional level but also between different jurisdictional levels. That is, the federal, state, and local agencies must cooperate. Agencies’ collective action failure will lead to wasteful duplication and the inability of agents at one jurisdictional level to inform agents at another level about a pending attack or threat. The creation of the Department of Homeland Security (DHS) in 2002 was, in principle, a move to eliminate waste and foster synergy among component agencies at all jurisdictional levels in the United States. Hearings following 9/11 revealed coordination errors, especially in terms of intelligence (National Commission on Terrorist Attacks Upon the United States, 2004, or 9/11 Commission Report). In the wake of 9/11, the US government had to take steps to provide Americans with a greater sense of security. Clearly, the ability of the 9/11 hijackers to bring weapons on board four flights demonstrated that the nation’s airports were not secure. The success of the terrorists in obtaining visas and even flight training in the United States also highlighted vulnerabilities. The failure of US law enforcement and customs officials to stop the terrorists at the border, even though some were on a watchlist, also reflected the system’s failure to protect Americans against terrorism prior to 9/11. On Christmas day 2009, Northwest Airlines flight 253 revealed that the “no-fly list” still presented gaps and challenges that allowed a bomb-carrying terrorist to board a flight. As a consequence, no-fly lists have been greatly expanded, and advanced imaging technology (AIT) scanners or “whole body imagers” will be increasingly deployed at US airports – 200 AIT units will be in place by the end of calendar year 2010, and a total of 878 AIT units will be in place by the end of the fiscal year 2014 (US Government Accountability Office, 2010).