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Alternative Perspectives on the Radicalization of Home- grown and “Leaderless” Terrorists

Two theories used to explain criminal behaviour are adapted here to provide an alternative means of understanding the radicalization of home-grown and “leaderless” terrorists.


Radicalization is a complex issue influenced by regional and country characteristics and dynamics as well as individual circumstances. However, another way of understanding the radicalization process of home-grown and “leaderless” terrorists could involve the use of theories that explain criminal behaviour. Two such theories are discussed here – Strain Theory and Differential Association Theory – with the aim of exploring how they can improve our understanding of radicalization in order to take better preventive action as well as design more suitable de-radicalization or disengagement programs.

Home-grown terrorists usually refer to individuals that are citizens or residents of the country they carry out acts of violence against. They may draw resources, expertise and leadership from external terrorist groups and networks, but this is not an essential characteristic as home-grown terrorists can also be “leaderless.” Leaderless terrorists usually have no connection to external terrorist groups or networks. They are individuals that are self-radicalized, typically through the Internet, and carry out attacks independently.

The radicalization process of home-grown and leaderless terrorists is not readily explained by existing models and theories. However, in order to develop effective preventive action against the emergence of such terrorists, their radicalization process must be thoroughly understood. In light of this, Strain Theory and Differential Association Theory, which originally seek to explain the causes of criminal behaviour, are adapted here to provide an alternative perspective.


Strain Theory

Robert Agnew’s General Strain Theory implies that strain is caused by a failure to achieve certain material goals. There are three parts to this: 1) the failure to achieve positively valued goods, 2) the removal of positively valued stimuli, and 3) the presentation of negative stimuli. Agnew acknowledges that individuals have varying abilities to cope with stress, peer influence, past experiences, socio-economic status and financial circumstances. Along with these, ethnic minority status and religious, cultural and linguistic differences between an individual and his peers will create strain on an individual in one way or another.

For instance, when an individual’s socio-economic status or discrimination due to being an ethnic or religious minority limits his or her ability to attain a college degree, this can reduce their opportunities to secure a well-paying job, which in turn affects whether they can realize their material desires. However these materialistic desires do not cease to exist even though they cannot be achieved, and strain occurs on the individual to achieve them at some point. One possible way for individuals to resolve this strain is to circumvent the limits on their socio-economic situation and status as a discriminated ethnic or religious minority through criminal means. This encapsulates Agnew’s assertion that the compulsion to commit a crime is a result of social strain. The same concept can be used to explain one part of home-grown terrorism involving leaderless, self-radicalized terrorists. A well-known example is that of Timothy McVeigh, nicknamed the Oklahoma Bomber. When the Oklahoma City bombing occurred in 1995, one of the immediate questions that arose was how did a former soldier who had served a tour of duty in Iraq turn into a home-grown terrorist?

Since young, McVeigh had a fascination for guns and the survivalist movement, which turned into obsessions by the time he was in junior high school. He joined the US military partly to satisfy his passion for weapons and survivalist behaviour, and partly out of frustration with a lack of employment opportunities. Having access to a number of weapons and a steady income was a positive stimulus to McVeigh. After his tour in Iraq during the first Gulf War, however, McVeigh was affected by failing to realize his goal of entering the US Special Forces. Furthermore, he also experienced removal of positive stimuli in the form of his friends in the military leaving for civilian life and the short conclusion of the Gulf War which robbed him of the chance to see extensive combat.

After McVeigh left the military at the end of 1991, he developed anti-government sentiments. He confided his fears about the government taking away his personal collection of weapons and published letters in local newspapers claiming that America was in decline. The presidency of Bill Clinton, which saw a campaign for gun control, presented a further removal of positive stimulus given McVeigh’s obsession with guns and his odd jobs in the gun show circuit.

However, from McVeigh’s own statements regarding why he carried out the Oklahoma City bombing, there were two major negative stimuli which combined with his anti-government sentiment and finally motivated him to carry out the attack. First, the shootout in August 1992 between federal agents and survivalist Randy Weaver, in which Weaver's wife and son were killed and second, the April 1993 siege at Waco in Texas during which members of a Christian sect were killed in a raid by federal authorities.

McVeigh’s example is thus a useful indicator of Strain Theory’s value in explaining the push and pull factors involved in the radicalization of leaderless home-grown terrorists. All three indicators of the theory – the failure to achieve positively valued goods, the removal of positively valued stimuli and the presentation of negative stimuli – are seen in this case.

Differential Association Theory

Edwin Sutherland’s Theory of Differential Association explains crime as a function of a learning process that could affect any individual from any background. The first principle of the theory states that criminal behaviour is learned through interactions with other persons. Although this seems an obvious fact, the theory elaborates that criminal behaviour is learned through intimate interactions within personal groups. Differential association may vary in frequency, duration and intensity. The extent to which criminal behaviour is learned thus depends on how it is reinforced through the interactions that take place in personal groups.

The same is also true of terrorist behaviour. A case study that can be used to illustrate this is that of Tamerlan Tsarnaev, one of the two brothers responsible for the Boston bombings in April 2013. In the year prior to carrying out the Boston bombing, Tamerlan Tsarnaev was reported to have spent six months in Dagestan, located in the North Caucasus region of Russia. During his time there, it is believed he came into contact with Dagestani militants during frequent interactions at a radical mosque. Furthermore, Tamerlan was actively engaged in online contact with other self-radicalized individuals such as William Plotnikov, a Russian-born Canadian who returned to Dagestan in 2010 to engage armed jihad.

Another important aspect that Sutherland identifies is the de-sensitization of individuals to criminal behaviour itself. When criminal behaviour is constantly discussed and idolized within a personal group, its legitimacy begins to shift. An illegitimate act can attain the status of perceived legitimacy and in some instances, righteousness. This aspect of Differential Association theory is particularly useful to explain the radicalization process when an individual comes into contact with a group of people that shares strong views and opinions. In the case of Tamerlan Tsarnaev, it is believed that his time in Dagestan, as well as his exposure to radical and extremist websites and literature de-sensitized his view of committing violence.



Strain Theory and Differential Association Theory provide useful insight into the radicalization of home-grown and leaderless terrorists. Strain Theory helps explain the push and pull factors during the process of radicalization as seen in the case of Timothy McVeigh, while Differential Association Theory can illustrate how the internet and intimate contact within personal groups facilitates leaderless terrorists’ radicalization. As more literature continues to emerge in the study of radicalization, the theories explored here point to a useful synergy that can be developed in future between theories used to explain criminal behaviour and theories that map out radicalization and seek to explain terrorist behaviour.


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