What Military Lessons can be Drawn from the Spectacular Terrorist Attacks on the United States on 11 September 2001?

“Never despise your enemy, whoever he is. Try to find out about his weapons and means, how he uses them and fights. Research into his strengths and weaknesses” asserted Field Marshal Prince Alexander V. Suvorov in 1789. In executing the most spectacular terrorist attacks in history in September 11th 2001 this is certainly what al-Qaeda did. To respond, the United States military must recognise the unconventional nature of its new opponent and greatly broaden its conception of threats and the means to counter them.

Within the military sphere there needs to be even more innovation to learn from the mistakes of September 11th and if the United States wishes to prosecute an effective counter-insurgency strategy throughout the Middle East further military transformations – in doctrine, formation, procedure, inter-service cooperation and technology – must be implemented and given the necessary funding and political support.

International insurgent terrorism, originating from abroad but existing in a nebulous, highly autonomous cell-based structure without state support or a single geographical base of operations marks an evolution in the development of terrorist action. The group behind the attacks of September 11th 2001, under the auspices of al-Qaeda and Usama bin Laden, utilised such innovative techniques and lateral thinking to such magnitude that scholars and policy-makers have heralded this as an entirely new form of terrorism. Regardless of the merits of such a distinction, for there is much argument that al-Qaeda is not fundamentally different from the ‘conventional’ terrorism of the IRA and PLO or that their conflict philosophy is especially different from that espoused by Karl Heinzen in the mid 19th Century[1], there is nonetheless much merit in identifying that in achieving such a spectacularly successful attack against the US homeland the United States military must re-orientate itself to fight a new kind of opponent. Some suggest that the characteristics of the emerging cell and column based international terrorist groups predispose them to a greater chance of success. The fundamental characteristics can generally be summarised as: Organised into groups of highly autonomous cells, referred to by Burton as columns[2], with each cell concentrating on one specialisation (command, intelligence, logistics, training, action &c.); a wider ‘network’ with intermittent communication, perhaps including a hierarchical element, but without centralised command and control; financial support established within the group infrastructure (commonly through illegal activities and wealthy individual sponsors)[3]; and operating under intense secrecy. However, one is not concerned with how new this terrorism is, but that its magnitude and form have propelled it to be the pre-eminent opponent of the United States’ armed forces. Consequently it is necessary to highlight how the international terrorist of the age of al-Qaeda is an entirely different opponent to the foes typically arrayed against the armed forces of a state.

Al-Qaeda and modern nihilistic strands of terrorism founded upon Islamic fundamentalism present a considerably problematic opponent to a conventional state armed force because of their apparent irrationality, willingness to die for their cause and refusal to negotiate as would most conventional foes (or conventional terrorists). As the Institute for Strategic Studies observe, “al-Qaeda seeks simply to produce as many casualties as possible without regard to a negotiated outcome”[4]and consequently are not compelled to practice operational restraint to maintain the prospect of political negotiation. Stevenson agrees with this assessment, arguing that “old terrorists are looking to bargain; new terrorists want only to express their wrath and cripple their enemy”[5]Therefore, conventional tactics engineered to force a military opponent to conduct negotiations cannot be effective when the political demands made by the terrorist are such that the policy-makers of the state cannot possibly entertain. Moreover, the extremism employed by terrorists often provokes the policy-maker into statements of refusal to negotiate even if it were a possibility. Further, Stevenson states that before September 11th “political approaches to representatives of ‘old’ terrorist groups could sometimes help tame them, only hard counter-terrorist measures such as law-enforcement and intelligence cooperation could contain the threat of new terrorism”[6]. Thus military objectives aimed at forcing an opponent to negotiate, either through battle victories or attempting to cut-off supplies is not viable because conventional victories are not possible when fighting international insurgent terrorists who have no desire to negotiate; their very nature, and the tactics they employ result in the only successful outcome for a state’s armed force is the existential annihilation of the terrorist group. Something which in itself is a military impossibility without a combined socio-political campaign to resolve the cultural determinants that give rise to the terrorists’ grievances.

The individual terrorists are not conventional soldiers. They may undergo significant training in tactics and techniques similar to the special forces of conventional armies, but they crucially remain closer to the civilian population from which they originated. Nor are they particularly distinguishable from the mass of the general population in outlook or psychological personality. It is a common misconception that a nihilistic terrorist would have certain behavioural abnormalities that could distinguish them from most other individuals, however as Duyvesteyn asserts, “there is no evidence of a terrorist personality, nor has there been a consistent finding of abnormality or derangement in persons involved in the undertaking”[7]. Silke supports this claim, arguing that research on the psychology of terrorists has found that “they are rarely paranoid, psychotic, fanatical, neurotic or psychopathic”[8]and further, that “all psychologists can safely say of terrorists is that their outstanding characteristics is their normality”[9]. Thus from the military perspective, the terrorist opponent is not necessarily irrational and is fully capable of logical and intelligent action, innovation and imagination in the execution of their plan of attack and willing to move within and without the civilian population when it most benefits their cause. The terrorist opponent is able to move freely within the civilian population because they are drawn from within it and often completely indistinguishable from the majority of ‘normal’ people in appearance and right up to the point of carrying out their mission, are practically indistinguishable in action. Consequently, conventional military forces cannot be employed effectively in counter-terrorism operations of this nature, instead one must rely on a selective use of special forces for surgical strikes working in close cooperation with HUMINT sources operated by the state, or friendly-foreign intelligence services. Moreover, there is a significant difficulty in operations within a foreign civilian environment because, as Silke recognises, “planned campaigns of violence do not happen within a vacuum and they are not driven by trivial or fleeting motivations that reside in and are shared only by the perpetrators”[10]but rather are manifestations of widespread grievances which are commonly shared by the civilian population, or if not wholly shared, are in accord with generally held sympathies. Therefore any special forces unit will be required to operate in a potentially hostile environment where the local population is willing to support the individual terrorist and hinder their apprehension.

The terrorist opponent also differs in that there is no single stereotype; no clear distinction of race, gender (although al-Qaeda operatives are typically male), age, class or material status. Consequently identification of such individuals is incredibly difficult. Nor are the terrorists of low intelligence, rather, they commonly have high levels of education, a comfortable socioeconomic status and stable family ties[11]. Indeed, according to Hoffman it is commonly the “most battle-hardened, skilled and dedicated cadre who enthusiastically volunteer to commit suicide attacks”[12]. A high level of intelligence and experience resulted in the September 11th attacks showing a “level of patience and detailed planning rarely seen among terrorist movements” and moreover, that the hijackers “stunned the world with their determination to kill themselves as well as their victims”[13]. Therefore the insurgent is equipped to easily intermingle in Western societies, combined with intense ingenuity and dedication, they can move freely without drawing undue attention from civilians or the authorities which makes them very difficult to counter using military units, special forces or not. Similarly, al-Qaeda has a cosmopolitan recruitment base that accentuates the difficulty in any systematic identification of terrorists; for example, Neumann states that the presence in Europe of “such a large pool of young, alienated Muslims presents Salafi jihadists with opportunities for recruitment and radicalisation which does not exist elsewhere”[14]. Further, Neumann claims that European terrorists “can utilise existing networks to facilitate planning and logistics, and take advantage of a less repressive political environment than in Middle East and North Africa”[15]. Therefore military forces cannot be employed against communities that exist in stable Western European democracies, which thus present other non-military challenges to the counter-terrorism effort. Furthermore, employing military units among the civilian population of a foreign state presents problems of increasingly the feelings of alienation and consequently driving more recruits into insurgent groups, as the German domestic intelligence service noted in that “statements rejecting the presence of the US military in Iraq as well as calls to fight the ‘occupiers’ and ‘torturers’ are amongst the most popular themes in Islamists’ efforts to win support”[16]. The dramatic success of the September 11th attacks and the sheer magnitude of response from the United States and international community has, Stevenson argues, “re-awakened dormant or demoralised terrorist groups and potential recruits to the considerable power of showcasing grievances by lethally attacking unsuspecting civilian targets”[17]. Similarly, that September 11th acted as a “stark reminder of asymmetric warfare’s primal ingredients: anger and resentment against American dominance and increasing access to the technological fruits of globalisation afford non-state and state actors alike the capacity to strike the US homeland and US overseas bases and friends”[18].

The 11th September attacks “transformed America’s longstanding sense of safety from foreign threats into a profound recognition of vulnerability”[19]. The tactics employed by bin Laden and al-Qaeda in executing the September 11th 2001 attacks are revolutionary, highly innovative and of an asymmetric type characteristic of the methods employed by irregular or special forces. Heavily outnumbered and out-resourced, special forces operate in a hostile environment with relatively few resources and limited windows of opportunity in attacking a more powerful foe. Insurgent terrorists, the like of the September 11th hijackers, operate precisely in this asymmetric branch of warfare. Unable to challenge the United States military in a conventional fashion, bin Laden and his cohorts orchestrated a plan to deliver as much damage to the United States as possible using the limited resources available to them, and without engaging America’s conventional armed forces through the unprecedented use of commercial aircraft as weapons. According to Hoffman “the enormity and sheer scale of the simultaneous suicide attacks on September 11 eclipsed anything previously seen in terrorism”[20]and has forced American military strategists to re-evaluate the national defensive posture of the United States and consider a far wider variety of potential methods for future terrorist attacks within the domestic United States. Furthermore, the military need to recognise the complexity of terrorist operations against the United States and its overseas interests, given that the September 11th attacks, while having such an ambitious scope, was nevertheless achieved through “impressive coordination and synchronisation”[21], and therefore the US military need to prepare for future attempts using unconventional tactics and previously unimaginable civilian resources and infrastructure as weapons. Terrorism, by its very nature, is considerably apart from the conventional warfare which American strategists had been prepared against. Barker and Ganor assert that the majority of analysts agree on three fundamental characteristics of terrorism; (1) the intentional use or threat of violence, (2) employed against civilian targets (3) to achieve political aims[22]. The nihilistic terrorism exhibited in September 11thnecessitates a broader definition to include an increased capacity for ruthlessness, a disregard for traditional humanitarian values and an aim to induce widespread fear in a population far greater in number than the potential victims of any immediate violence, through the selection of targets with important national symbolism and a key constituent of the national identity. Consequently, the United States has had to increase security not only to sights of strategic importance but also to those with symbolic importance. Therefore, September 11th highlighted to the US military that terrorist attacks are likely to increase against targets with no military significance and therefore considerable resources must be reorganised and assigned to locations previously considered as unlikely military targets.

September 11th revealed worrying deficiencies in defensive strategy for the US homeland because the principal strategic thinkers had not taken into consideration the possibility of a small party of terrorists hijacking an aircraft and using it as a high-velocity, high explosive flying-bomb. Spectacular terrorist attacks prior to September 11thmade use of largely conventional small-yield explosives with limited targets and were themselves a relatively uncommon occurrence. Hoffman speculates that the rarity of large-scale coordinated attacks was because previous terrorist organisations lacked the logistical and organisational complexity that has become associated with al-Qaeda[23]. In contrast to old-style terrorist organisation, al-Qaeda and modern insurgent terrorists make use of modern technology, high-speed communication and extremely complex strategic planning and management of resources. Bin Laden himself had considerable experience managing a profitable international family business and had proven the effectiveness of such management and leadership when applied to a terrorist organisation while fighting the Soviets in Afghanistan. The United States were, Hoffman argues, mistaken in believing that “mass, simultaneous attacks in general and those of such devastating potential as seen in New York and Washington on September 11 were likely beyond the capabilities of most terrorists”[24]. Such an inability to imagine the complexity of terrorist organisations and the far more considerable resources they could employ in the prosecution of attacks, designed to exploit the weakness in the United States while maximising the few strengths of the terrorists, resulted in the United States as unprepared for the 11th September attacks and being caught with complete strategic surprise. US air defence was not prepared to counter the attacks because there was no set of protocols in place to deal with an internal attack of this nature; resources were not allocated to the defence of symbolic targets nor domestic military command infrastructure, and what few aircraft could eventually be dispatched from the North American Aerospace Defence Command (NORAD) were ill-equipped to respond to the use of commercial aircraft as a threat because they had not previously been thought as a likely threat scenario. Gormley supports this argument, documenting that the “head of the [US] Defense Protective Service indicated that their attack scenarios all assumed that any airborne threat would involve a small propeller powered commuter aircraft accidentally hitting the Pentagon”[25]. Thus,

“Attention was also arguably focused too exclusively either on the low-end threat posed by car and truck bombs against buildings or the more exotic high-end threats, against entire societies, involving biological or chemical weapons or cyberattacks. The implicit assumptions of much of American planning scenarios on mass casualty attacks were that they would involve germ or chemical agents or result from widespread electronic attacks on critical infrastructure… The lesson, accordingly, is not that there need be unrealistic omniscience, but rather that there is a need to be able to respond across a broad technological spectrum of potential adversarial attacks”[26].

Carter claims that the ‘security institutions of the US federal government are particularly ill-suited to deliver homeland security’[27]. The 2003-2004 Strategic Survey supports that US domestic security has not kept pace with its foreign military policy rather that it has been “slow, inconsistent and under-resourced”. Further, the IISS argue that despite several years of ‘intensive interest’ in developing an effective array of homeland security measures state infrastructure “remains considerably exposed” and adequate progress has not been made in preparing for an emergency response[28]. Furthermore, the Western-world’s reliance on technology to manage key political, economic and military assets provides potential terrorists with another avenue for attack. White recognises that the US is “dependent on technology” and that while great efforts have been made to secure military targets against technological attack, “civilian industry has fallen behind”. The International Institute of Strategic Studies identifies technological and internet-based infrastructure as particularly vulnerable to attack. Indeed, it identifies that attacks “would have far reaching ramifications for the government and private sector ranging from economic trauma to hindering consequence-management operations”[29].

Therefore, US defensive strategy lacked the innovation and imagination necessary to think outside the traditional Cold War paradigm of state-centric threats to national security and consequently was found severely unable to counter the terrorist attacks on the World Trade Centre and Pentagon. Imaginary strategic planning, perhaps assisted by implementing the ‘red teaming’ suggested by the Defense Science Board, would be a significant positive step in preparing the United States for the future possibilities of terrorism. Hoffman again highlights just how innovative al-Qaeda were, in stating that “until the attacks on the World Trade Center and Pentagon, no single terrorist operation had ever killed more than 500 persons at one time”[30]and that the number of casualties in 90 minutes on 11thSeptember 2001 exceeded by a magnitude of three the number of American casualties to terrorism in the previous thirty years. Thus, one of the enduring military lessons that has arisen from September 11th is the necessity for consistent lateral thinking in identifying possible threats to the US and its interests. The US governments 2006 Quadrennial Defense Review affirmed the new concentration on capabilities-based planning that seek to “identify specific capabilities needed to deter or defeat adversaries who will employ surprise, deception and asymmetric forms of warfare” therefore developing capabilities to “handle a full range of likely future contingencies”[31]. Similarly, September 11th “underscored the need for considerably greater flexibility to configure forces to enable them to respond quickly to a variety of diverse contingencies”[32]within the United States and in overseas theatres.

In US homeland defence military power has an important part to play in providing missile defence against ballistic and cruise missile attacks[33]especially in the mindset of US strategic planners who perceive the possibility of determined terrorists gaining possession of long-range ballistic missiles as an ever-increasing possibility[34]. Moreover, September 11th highlights how the US defence community needs to examine the application of a missile defence system that can counter unconventional air attacks within the domestic United States, particularly the use of unmanned aircraft that can now be acquired for relatively little cost and thus small kit aircraft flying at under 80 knots could go unnoticed on legacy air-defence radar which eliminates “slow-moving targets on or near the ground to prevent their data processing and display systems from being overtaxed”[35]. However, as Gormley and the IISS recognise, air defence systems in the mainland US have experienced staggering delays, technical problems, insufficient funding[36], lack service interoperability and therefore are unsuited for implementation to counter rapidly emerging threats[37]. Moreover, the proliferation of LACMs (land attack cruise missiles) could, as Gormley asserts, pose significant problems for the delivery and employment of US armed forces in overseas staging bases and foreign regional bases of operations, which would be necessary for long-term counter-terrorist and counter-insurgency campaigns.

The changing face of the opponent following September 11th has dramatically altered the combat environment that conventional and special forces will be operating within in counter-terrorist and counter-insurgency operations. The capabilities-based strategy of the US military has given rise to a concept of pre-emption that seeks to neutralise future threats before they are allowed to realise their full potential. This has wide-reading military implications for the employment of force, and will require significant interoperability and cooperation between the armed services, and, crucially, implies a closer connection between conventional armed forces and their special operations counterpart to the extent that conventional force elements could be embedded within special forces units. This is necessary because, as the IISS recognise, “the principle measure of effectiveness would be represented less by the number of weapon platforms that could be brought to bear on the enemy than by the quality of networking between sensors and shooters… high-speed, high-capacity communications networks would enable the precise application of force against the most important enemy targets”[38]. Employed to great effect in the battle for Mazar e-Sharif in Afghanistan, precision ground-based targeting of airstrikes by USAF combat air controllers embedded within Special Forces ‘A’ teams dramatically increased the effectiveness of precision air strikes on Taliban and al-Qaeda targets by decreasing the time-lag between targeting and delivery to within minutes rather than hours[39]. Consequently, this demonstrated “for the first time how airpower can be employed in near-simultaneous rather than sequential form due to the rapid integration of sensor data into the allocation of airpower”[40], broke down institutional barriers that had prevented the integration of special operations forces with conventional capabilities [41] and illustrated the potential of network-centric warfare (NCW) in allowing armed forces to mass effects without massing forces and therefore decreasing unit vulnerability when fighting against insurgents in a hostile environment. Furthermore, the difficulty of the diverse and unconventional operating environments accentuate the requirement for technical innovation to support the tactical; foliage penetration radar, variable effect ‘dial-a-yield’ munitions, breakthroughs in wide-area surveillance and instantaneous filtering and selection of targets are just some of the transformative military technologies necessary to effectively prosecute a ‘long war’ against terrorist and insurgent organisations. Conventional American military strengths produce very uncertain advantages in highly asymmetric conflicts, therefore large-scale and varied transformations in strategic oversight, tactical and operational conduct and technology are some of the military lessons that can be drawn from September 11th 2001 and its consequences.


  • Baker, J. (2003) The No-Nonsense Guide to Terrorism. London: New Internationalist
  • Burton, A. (1976) Urban Terrorism. New York: Free Press
  • Carter, A. (2002) ‘The Architecture of Government in the Face of Terrorism’. International Security 27 (3)
  • Duyvesteyn, I. (2004) ‘How New Is The New Terrorism’. Studies in Conflict & Terrorism 27
  • Gormley, D. (2002) ‘Enriching Expectations: 11 September’s Lessons for Missile Defence’. Survival 44 (2)
  • Heinzen, K. (1848)Murder, in Laqueur W. & Alexander, Y. (ed.) (1987) The Terrorism Reader. New York: Meridian
  • Hoffman, B. (2002) ‘Rethinking Terrorism and Counterterrorism Since 9/11’. Studies in Conflict & Terrorism 25
  • International Institute for Strategic Studies (2002) ‘Countering Terror after 11 September, Early Lessons, Future Challenges’. The Military Balance 102 (1)
  • International Institute for Strategic Studies (2002) ‘US Military Transformation after 11 September’. Strategic Survey 102 (1)
  • International Institute for Strategic Studies (2003) ‘Getting Homeland Security Right’. Strategic Survey 2003-2004
  • Neumann, P. (2006) ‘Europe’s Jihadist Dilemma’. Survival 48 (2)
  • Silke, A. (2003) ‘Beyond Horror: Terrorist Atrocity and the Search for Understanding’. Studies in Conflict & Terrorism 26
  • Stevenson, J. (2001) ‘Pragmatic Counter-Terrorism’. Survival 43 (4)
  • White, J. (2003) Terrorism. Canada: Wadsworth


[1]Heinzen, K. (1848) Murder, in Laqueur W. & Alexander, Y. (ed.) (1987)The Terrorism Reader. New York: Meridian

[2]Burton, A. (1976) Urban Terrorism. New York: Free Press.

[3]White, J. (2003) Terrorism. Canada: Wadsworth.

[4]International Institute for Strategic Studies (2002) ‘Countering Terror after 11 September, Early Lessons, Future Challenges’. The Military Balance 102 (1), p. 237

[5]Stevenson, J. (2001) ‘Pragmatic Counter-Terrorism’. Survival 43 (4), p. 35


[7]Duyvesteyn, I. (2004) ‘How New Is The New Terrorism’. Studies in Conflict & Terrorism27, p. 441

[8]Silke, A. (2003) ‘Beyond Horror: Terrorist Atrocity and the Search for Understanding’. Studies in Conflict & Terrorism 26, p. 38

[9]ibid., p. 54


[11]Hoffman, B. (2002) ‘Rethinking Terrorism and Counterterrorism Since 9/11’. Studies in Conflict & Terrorism 25, p. 305


[13]ibid., p. 304

[14]Neumann, P. (2006) ‘Europe’s Jihadist Dilemma’. Survival 48 (2), p. 73

[15]ibid., p. 78

[16]ibid., p. 76

[17]Stevenson, op. cit., p. 36

[18]Gormley, D. (2002) ‘Enriching Expectations: 11 September’s Lessons for Missile Defence’. Survival 44 (2), p. 24

[19]IISS ‘Countering Terror’, p. 237

[20]Hoffman, op. cit., p. 304


[22]Baker, J. (2003) The No-Nonsense Guide to Terrorism. London: New Internationalist, p. 23

[23]Hoffman, op. cit., p. 304

[24]ibid., p. 305

[25]Gormley, op. cit., p. 24

[26]Hoffman, op. cit., p. 306

[27]Carter, A. (2002) ‘The Architecture of Government in the Face of Terrorism’. International Security 27 (3), p. 16

[28]International Institute for Strategic Studies (2003) ‘Getting Homeland Security Right’. Strategic Survey 2003-2004, p. 51

[29]ibid., p. 58

[30]Hoffman, op. cit., p. 304

[31]Gormley, op. cit., p. 22

[32]International Institute for Strategic Studies (2002) ‘US Military Transformation after 11 September’. Strategic Survey 102 (1), p. 75

[33]ibid., p. 237

[34]Gormley, op. cit., p. 19

[35]ibid., p. 26

[36]IISS ‘Countering Terror’, p. 237

[37]Gormley, op. cit., p. 28

[38]IISS ‘Countering Terror’, p. 232

[39]ibid., p. 233

[40]ibid., p. 235

[41]IISS ‘US Military Transformation’, p. 71

Written by: Oliver Lewis,
Written at: University of Wales, Aberystwyth

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