International Relations and political violence: A study of the causes of domestic Jihadist violence in a transatlantic context

How can homegrown jihadist violence (HJV) in the West be explained using the levels of analysis? Addressing this question helps provide a clearer image of the HJV phenomenon, allows us to categorize causes of HJV from micro to macro levels, and adds new insight to the debate on causes of the problem. As an important international security and political violence issue, HJV has received great scrutiny by scholars in the past fifteen years. However, no one has provided a cross-level analysis of its causes through the lens of the levels of analysis framework. ¹ This paper seeks to fill the gap by applying the International Relations’ (IR) levels of analysis framework, conventionally used for studying international and inter-state issues, to the study of HJV. ² By bringing the IR’s levels of analysis literature into conversation with the radicalization to violence literature, this paper provides a multidisciplinary and multi-level analysis of HJV. While applying this IR theoretical model to the study of an asymmetric security problem from the political violence field helps enrich both fields, it also emphasizes the need for using conventional theories in explaining novel international issues.

The HJV is also known in the literature as homegrown terrorism or extremism, as well as domestic terrorism. ³ In this paper, it refers to jihadist activities that have occurred as lone-wolf or small cell plots and/or attacks in Western cities since the Madrid train bombings in 2004. Those activities are carried out by individuals, “who were born and raised in the West or have a strong attachment to the West,” or who have resided for an extended period of time in Western countries and, at the same time, are inspired and radicalized by a particular strand of Islamist ideology called Jihadi Salafism. ⁴ Depending on their personal preferences, social networks, and relationship with major jihadist organizations, some of those individuals attack at home while others travel abroad and join major jihadist organizations to take part directly in global jihad or to receive training and come back to plot attacks and/or motivate recruits in Western cities. ⁵

Data show that a high number of post-9/11 Islamist violent events in the West have been homegrown. ⁶ Although the far-right violence by neo-Nazis and white supremacists have become a growing and most significant political violence in Western countries in recent years, it does not mean that the HJV is not important anymore. ⁷ Research shows that, despite the military defeat of terrorist organizations such as al-Qaeda and Islamic State of Iraq and Syria (ISIS) in the Middle East, “basic causes and conditions fomenting extremism” have not changed much since 9/11. ⁸ What are those persistent and yet non-transformative causes and conditions that give rise to such a complex phenomenon? While scholars have addressed this question using a variety of perspectives, an analytical framework is needed to categorize those causes according to a range of micro and macro levels. ⁹ By applying IR’s levels of analysis, this paper seeks to present such a framework that helps categorize and study the root causes of HJV at individual, group, and international levels.

This research is based on three qualitative case studies, including the London bombings (7 July 2005), the Toronto 18 plot (2006), and the Boston Marathon bombings (2013). Three factors inform case selection. First, the three case studies allow for a careful examination of many variables identifiable at all three levels in major countries on both sides of the Atlantic. Second, every case captures descriptive features of HJV and, therefore, the three cases are intended to provide a representative image of the problem in a transatlantic context. Finally, these cases have been widely reported upon, facilitating access to original and secondary data.

The remainder of this paper is organized as follows. First, I articulate the literature on HJV. Second, I discuss the levels of analysis framework, and its application to the study of HJV. The next three sections are dedicated to case studies. In the subsequent section, I examine HJV causes in a cross-level context and investigate the relationship between causes belonging to different levels. In conclusion, I discuss the findings and their contribution to the literature and policy.

The debate

In the past 15 years, the HJV phenomenon has been an important research topic for IR and political violence scholars, leading to a vast and multidisciplinary literature. I categorize this literature into three clusters: the process-based literature; the environment-based literature; and the multiple-factor-based literature.

The process-based literature mostly focuses on the process of radicalization of individuals and their progress toward HJV in different stages and trajectories. From this perspective, which mainly concentrates on causes at the individual level, HJV emerges as an outcome of a potential individual or a group of individuals’ progress from one to another stage of extremism. The underlying force behind this process includes a series of individual-level causes, such as personal crisis, isolation, feeling of injustice, the experience of discrimination, and feeling of attachment to a broader identity. ¹⁰

By contrast, the environment-based literature focuses on socioeconomic, cultural, political, and international environments as conditions that might radicalize individuals and, eventually, lead them to commit HJV that might motivate potential individuals to radicalize and, eventually, to commit HJV. From this perspective, which mainly concentrates on causes at the structural/environmental level, factors such as immigration and integration shortages, the globalization of militant Islamism, international politics in the Islamic world, and cultural alienation create an environment that makes potential and vulnerable individuals receptive to the jihadist call. HJV emerges as a result. ¹¹

Finally, the multiple-factor-based literature seeks to aggregate multiple causes of HJV in single accounts in order to develop policy-relevant research. From this perspective, which mainly concentrates on causes at social and/or political levels, different factors in different national and transnational contexts motivate individuals toward radicalization to violence that eventually leads to HJV. ¹²

The three clusters of the literature investigate the HJV phenomenon broadly and deeply, and from a variety of perspectives. Yet, an articulation and examination of the causes of HJV through the levels of analysis lens would help provide a more systematic assessment and explanation of the problem. Drawing on insight from the IR’s levels of analysis literature, the political violence literature, and the HJV literature, this paper seeks to contribute to the latter by bringing the three literatures into conversation.

The levels of analysis, political violence, and HJV

The term levels of analysis was first used by Singer (1961) who initially formulated the causes of international events at two levels: the state; and the international system. ¹³ Although Waltz (1954) had already developed the three images of international politics, he had not used the levels of analysis language until writing his Theory of International Politics, originally published in 1979. Following Waltz’s popular work, the levels of analysis framework became a focal point of debate in the IR literature.

Among others, Most and Starr (1989) developed the framework into a model that includes flexible sets of variables, categorized from least abstract to most abstract, within each level. These variables then interact in a cross-level manner. ¹⁴ Thus, Most and Starr integrated the structural and actor-oriented variables into a single analytical model that includes two flexible sets of variables belonging to the willingness and opportunity contexts. ¹⁵ In this model, the relationship among causes at different levels of analysis is considered an important aspect of the causal mechanism. For example, when an actor or a group of actors claim that there was, “no other alternative than to go to war,” they indicate and justify their willingness to choose war. ¹⁶ However, factors belonging to willingness require the opportunity, based on capabilities and possibilities, to take the action. Therefore, the distribution of opportunities means that some actors, regardless of their level of willingness, will have the ability to take the action that others will not. Likewise, the provision of opportunities at the structural level requires willingness at the individual level and both willingness and opportunity at the group/state level because the second level in this formulation, “can be seen as containing elements of both opportunity and willingness.” ¹⁷

Therefore, in Most and Starr’s model, the emphasis is not on whether variables belonging to willingness (i.e., decision-makers willingness to utilize force) is more important than variables belonging to opportunity (i.e., structurally engendered opportunities to initiate a decision) or vice versa. Rather, the emphasis is on the importance of every variable at each level of analysis and their interaction in producing a single outcome. ¹⁸ Thus, factors belonging to both willingness (at individual and group levels) and opportunity (at the international or structural level) exist and interact before an outcome emerges. This method moves beyond the reductionist and micro-level decision theory and expands the causal mechanism into a framework that explains not only the impact of every single cause on the outcome but also the amalgamated role of causes belonging to all levels in producing the outcome. ¹⁹ In this model, the first level of analysis includes individual actors and their willingness to act; the second level includes a group of actors and both the willingness and opportunity that motivate and prepare them for action; and the third level includes the environment that defines the opportunities (in terms of possibilities and capabilities) for the action. ²⁰ The application of this framework to the study of HJV allows us to investigate and categorize the causes of this phenomenon at individual, group, and international levels and to discover the cross-level relationship between causes belonging to different levels of analysis.

At the individual level, terrorism studies scholars suggest that terrorist behaviour is the result of interrelation between an individual’s behaviour and the social, political, and ideological contexts that motivate the individual to demonstrate a violent behaviour. ²¹ Therefore, individual psychology is influenced by social or group psychology that directs the individual towards violence. ²² Social psychology, in this sense, is conceived as a context that affects individual psychology in producing a multiplicity of motivations, including a sense of revenge and a sense of gaining significance. ²³ HJV, in this context, can be explained as an outcome of causes produced in a social, political, and ideological environment that pre-exists and motivates potential individuals to become violent agents. In light of this discussion, the root causes of HJV could include a personal motivation for jihad and a desire for heroism that are affected by social psychology, produced in a particular environment. For example, the London bombers of July 2005 were deeply influenced by a personal desire for jihad and contribution to al-Qaeda’s international jihadism. This personal motivation was produced in a social and international environment influenced by the British government’s involvement in the invasion of Afghanistan and occupation of Iraq. ²⁴

At the group level, scholars believe that ideology, as a belief system and a shared reality, helps individuals to formulate and reinforce a group identity as we that then help them define an enemy as others. ²⁵ A review of the HJV cases shows that almost all domestic jihadi actors in the West made their decisions under the influence of jihadi Salafism as a group ideology. Jihadi Salafism, in this context, produced causes at the group level. Empirical evidence on HJV shows that most individuals who committed terrorist plots and/or attacks aimed to serve the causes defined by the jihadi Salafi ideology and propagated by major jihadist organizations such as al-Qaeda and ISIS. For example, the two ringleaders of the Toronto 18 plot were deeply under the influence of jihadi Salafi texts and videos, particularly those produced by al-Qaeda. From the early stages of radicalization to preparation for the, “Battle of Toronto,” the two individuals indicated an ideological commitment to jihadi Salafism and al-Qaeda’s purposes. ²⁶

At the international level, several factors relating to international politics and Western powers’ policies in the Islamic world can be defined as the root causes of HJV. Theories belonging to this level of analysis describe international causes as external constraints that encourage and even compel actors to react violently. ²⁷ Concerning HJV, a series of elements concerning international politics in the post-9/11 context, particularly Western countries’ military engagement in Afghanistan, Iraq, and elsewhere, defines the root causes of this phenomenon at the international level.

Although modern jihad’s globalization is linked to the Soviet Union’s invasion of Afghanistan during the 1980s, when tens of thousands of jihadi fighters from all around the Islamic world travelled to Afghanistan to fight a common enemy, ²⁸ it became more intense, large scale, and Western-centric with the emergence of al-Qaeda and its 9/11 attacks. In this new context, jihadist organizations justified their violent actions as reactions to United States’ foreign and military policies in the Islamic world. ²⁹ Homegrown terrorists in the West, inspired and influenced by this new worldview, also justified their activities as a response to the United States and its allies’ military interventions in Islamic countries. For example, the London bombers of July 2005 described their action as a way to put pressure on the British government to withdraw troops from Afghanistan and Iraq. Similarly, the mastermind of the Boston Marathon bombings (2013) perceived violence as a response to the United States’ involvement in, “other people’s [Islamic countries] affairs.” ³⁰ The complexity and dynamics of HJV are investigated in detail through separate case studies in the following sections. Each case study categorizes and investigates causes from micro to macro levels, explaining how multiple factors at individual, group, and international levels led to the emergence of the case.

The London bombings (2005)

The London bombings refers to a series of terrorist attacks on London Public Transport by four British citizens on 7 July 2005, killing 56 people, including the bombers, and injuring 700. Three of the bombers (Mohammad Sidique Khan, Hasib Mir Hussain, and Shehzad Tanweer) were born in the United Kingdom from parents of Pakistani origins, and the fourth bomber (Germaine Maurice Lindsay) was born in Jamaica, immigrated to the United Kingdom at the age of five, and converted to Islam at age 17. ³¹

According to profiles of the four bombers, they came from a variety of socioeconomic and educational backgrounds and were radicalized at different stages of life by a variety of factors. Despite their different backgrounds, a shared motivation for taking part in the post-9/11 global jihad connected the four individuals, putting them in a common direction. In other words, what brought the four bombers together was not their personal experience or family background, but their common motivation to contribute to al-Qaeda’s global jihad and respond to the British government’s participation in the invasion of Afghanistan and the occupation of Iraq. In many other similar cases, too, motivation went beyond individual jihadists’ personal desire for contribution to al-Qaeda’s cause. Western governments’ post-9/11 foreign and military policies in the Islamic countries justified violence in Western cities. ³² These root causes of the London bombings are categorized and explained at individual, group, and international levels of analysis in this section, and their interaction is examined within the opportunity and willingness contexts in a later section.

At the individual level, the four bombers were influenced by personal desire for jihad and a quest for significance through a contribution to al-Qaeda’s global jihadism. ³³ In this context, heroism and personal desire to participate in the post-9/11 global jihadism provided the underlying forces behind the four bombers’ decision to commit the terrorist act. There are remarkable documents, inquiries, and statements by the bombers that provide empirical support for this argument. For example, Sidique Khan’s videotaped statement, released by the media on 1 September 2005, indicates Khan’s desire for heroism and personal motivation to contribute to al-Qaeda’s cause. In a part of his statement, Khan links his terrorist act to global jihadism, paying tribute to individuals who claimed to lead the post-9/11 global jihad:

I myself, I myself, I make dua (pray) to Allah… to raise me amongst those whom I love like the prophets, the messengers, the martyrs and today’s heroes like our beloved Sheikh Osama Bin Laden, Dr. Ayman al-Zawahiri and Abu Musab al-Zarqawi and all the other brothers and sisters that are fighting in the… of this cause. ³⁴

The official profile of the London bombers indicates that Khan and his fellow bombers took their first steps toward radicalization and terrorism with a local gang in Beeston. The gang was known as the “Mullah Crew” and, “reportedly took on the task of cleaning up young drug addicts, taking them on outdoor pursuits activities such as white-water rafting and paintballing.” ³⁵ The Mullah Crew also introduced the future bombers to local radical Islamist circles, such as the Iqra Islamic bookshop, a popular spot for Islamist elements. ³⁶ At Iqra, by 2002, the four bombers developed a stronger ideological connection. ³⁷ However, it was not until they developed mental and ideological connections with al-Qaeda and its global jihadist cause that they were prepared to carry out a violent action. The feeling of connection to al-Qaeda and its cause turned the young Islamists into global jihadists. The bombers’ behavioural change toward violent extremism was quick, and their motivation to conduct terrorism was influenced more by external factors, particularly al-Qaeda and the global jihadist propaganda, than their socioeconomic or cultural backgrounds.

At the group level, two root causes of the London bombings can be explained by elements of jihadi Salafi ideology. ³⁸ Before making the final decision, the four bombers were deeply influenced by the jihadi Salafist ideology, which they had internalized through both direct contacts with like-minded individuals at the Iqra Islamic bookshop and on the Internet. The bombers were influenced by all four elements of jihadi Salafi ideology (i.e., the definition of a problem that Muslims face, an enemy that causes the problem, a method to fight the enemy, and a goal). ³⁹ For example, according to his videotaped statement, Khan’s motivation for jihad, his religious justification for the violent action, and his definition of his jihadi cause reflect the bomber’s intense religiosity and his reliance on jihadi Salafism and its fourfold criteria. ⁴⁰ Although interviews with people who knew the bombers provide information about their diverse personalities and social lives, other data and the bombers’ statements provide evidence for their shared influence by the jihadi Salafi ideology. ⁴¹ These data and statements show four bombers driven by the idea of global jihad against the Western invasions of Muslim territories in a post-9/11 context. The causal impact of the jihadi Salafi ideology on the London bombers and their motivation to participate in al-Qaeda’s global jihad links the group-level causes to the international-level causes.

At the international level, the four bombers were reacting to the British government and its allies’ foreign and military policies in the Islamic world, particularly the British government’s participation in the invasion of Afghanistan (2001) and occupation of Iraq (2003). It is worth noting that Western citizens’ engagement in jihad before 9/11 was influenced by other foreign policy factors, such as Western countries’ support for Israel, the United States’ deployment of troops in Saudi Arabia following the Gulf War, violence in Kashmir, and other issues. ⁴² However, the post-9/11 jihadist-oriented violent actions in the West, like the London bombings, were produced in an international environment largely influenced by al-Qaeda and its offshoots, as reactions to Western governments’ military engagement in the Islamic world.

The influence of international factors on the London bombers’ decision to take part in al-Qaeda’s global jihad is reflected both in their statements and in the official case inquiries. For example, in his famous 2005 statement, Khan simultaneously explained and justified his decision to engineer the London bombings as a response to Western government intervention in Islamic countries:

Your democratically elected governments continuously perpetuate atrocities against my people all over the world. And your support of them makes you directly responsible, just as I am directly responsible for protecting and avenging my Muslim brothers and sisters. Until we feel security, you will be our targets. And until you stop the bombing, gassing, imprisonment, and torture of my people we will not stop this fight. We are at war and I am a soldier. Now you too will taste the reality of this situation. ⁴³

In line with Khan’s statement, in a separate videotape released by the media on 6 July 2006, another bomber, Shehzad Tanweer, described the bombing as a response to the British invasion of Afghanistan and occupation of Iraq. ⁴⁴ Addressing the British government, Tanweer described the bombings as, “only the beginning,” of attacks and emphasized that they would continue until the withdrawal of British forces from Afghanistan and Iraq and the end of the British government’s, “financial and military aid to America and Israel.” ⁴⁵ Both statements indicate the significant and determinant influence of international factors in the London bombings and explain the causal link between a particular aspect of post-9/11 international politics and the bombers’ motivation to respond to it with violence.

The Toronto 18 plot (2006)

The Toronto 18 plot is, “the most prominent case,” of HJV in Canada, ⁴⁶ the name of which was inferred from the network’s number of members and their place of residence. ⁴⁷ A jihadi network of 18 individuals were arrested in June 2006 while planning a series of high-casualty attacks on several high-profile targets in the province of Ontario, including “the Toronto Stock Exchange, the Front St. offices of Canada’s spy agency, and a military base off Highway 401 between Toronto and Ottawa.” ⁴⁸ The group comprised two connected networks operating in two suburbs of Toronto (i.e., Mississauga and Scarborough). ⁴⁹

Research shows that the network’s two ringleaders, Afghanistan-born Fahim Ahmad and Jordan-born Zakaria Amara, were highly influenced by jihadi Salafi ideology and also motivated by other factors at individual and international levels. ⁵⁰ Because the Toronto 18 Plot was shaped and led by the two ringleaders, this case study investigates the two individuals’ background and their motivation at individual, group, and international levels. ⁵¹ Moreover, since the Toronto 18 case indicates a significant interconnection between causes belonging to individual and international levels, it is important to investigate the two clusters of causes together. The two ringleaders’ motivations for the terrorist plot at individual and international levels are interconnected. Their personal desire to contribute to al-Qaeda’s global jihadist campaign was shaped in a specific international context in the aftermath of the 9/11 attacks.

The connection and friendship between Ahmad and Amara go back to their teenage years in the early 2000s when they were students at Meadowvale Secondary School, Mississauga, Toronto, where the two friends also met Saad Khalid, who also played a key role in the plot. The three teenagers became influential members of the Muslim Students Association, initially created to help, “dissatisfied youth.” The friends shared many commonalities, including, “political concerns related to the suffering of Muslims in conflicts around the world.” ⁵² In the Muslim Students Association, the three persons joined other dissatisfied individuals and became more reactive to international politics in the Islamic world, particularly the Western military invasion of Afghanistan and Iraq. At this stage, besides increasing connections with like-minded individuals, the two ringleaders began learning about major jihadi organizations, their ideology, and terrorist tactics.

In particular, the two ringleaders (and members of their network) were personally motivated by both anger against Western policies in the Islamic world, particularly the Canadian military intervention in Afghanistan, and the perceived heroism that comes from taking part in al-Qaeda’s global jihadi campaign. Thus, while individual-level factors, such as anger and a quest for significance, caused the decision to act violently, the plot was also shaped in a specific international environment, defined by al-Qaeda’s global campaign and Western governments’ military policies in the Islamic world, particularly the Canadian government’s military engagement in Afghanistan. As such, the plot evolved simultaneously as both an outcome of the two ringleaders and their followers’ personal desire for jihad and their reaction to Canadian military presence in Afghanistan. ⁵³

In addition to causes at individual and international levels, the Toronto 18 Plot was also influenced by causal factors at the group level. At this level of analysis, the influence of the jihadi Salafi ideology provided the causal factor for the Toronto 18 case. The two ringleaders, Ahmad and Amara, showed clear tendencies toward al-Qaeda and its violent project only after they gained access to jihadi Salafi materials through the Internet and interaction with like-minded individuals at the local Salaheddin Islamic Centre, Toronto. ⁵⁴ Influenced by these texts and videos, the two ringleaders were pushed toward higher stages of radicalization and took practical steps toward mobilization to violence. The network of 18 individuals who initially gathered to read Salafi texts, watch jihadi videos, and discuss international politics was created at this stage. ⁵⁵ By December 2005, the network established a training camp in Toronto where they gathered regularly, watched jihadi videos, and listened to jihadi sermons. ⁵⁶ In one such session, Ahmad himself gave a sermon in which he likened his network to al-Qaeda, emphasizing, “the same aims, objectives, and methods.” ⁵⁷ In their meetings, the network members repeatedly mentioned al-Qaeda messages, such as “Martyrs of the Confrontation,” as a source for their decision and wished to fulfill al-Qaeda-like operations. ⁵⁸ Their activities and approach to violence, in this sense, reflects all four key elements of jihadi Salafi ideology, including the definition of an international problem in the Islamic world (i.e., the Western invasions), perception of an enemy that caused the problem (i.e., Western governments), preference of violence in the form of a jihadi operation against the enemy, and a goal (i.e., a contribution to the global campaign of major jihadi Salafist organizations, particularly al-Qaeda). As such, jihadi Salafism not only provided the group-level cause of the Toronto 18 plot, but it also functioned as a unifying force that led the network’s members in a common direction.

The Boston Marathon bombings (2013)

The Boston Marathon bombings refers to two explosions during the annual Boston Marathon on 15 April 2013 that killed three and injured 264 people. The bombings were carried out by a US permanent resident of Chechen descent, Tamerlan Tsarnaev, who was killed during the manhunt for the bombers, and his younger brother Dzhokhar Tsarnaev (a United States citizen), who was arrested after the bombings and sentenced to death in April 2015. Investigators found that the bombers, particularly the older brother, Tamerlan, were religiously motivated and inspired by the jihadi Salafist ideology. They aimed to take part in the global jihadist campaign through the bombings. ⁵⁹ However, despite the bombers’ commitment to jihad Salafism and its globalist cause, data do not prove any direct connection between them and a jihadist organization, such as al-Qaeda. ⁶⁰

Overall, the bombings were the outcome of causes at all three levels of analysis. The event’s mastermind, Tamerlan, who influenced and encouraged his younger brother, Dzhokhar, to take part in his jihadist project, was personally inspired by al-Qaeda and its jihadist ideology and was reactive to international politics, particularly United States’ engagement in the Islamic world. ⁶¹ Since the older brother acted as the mastermind and leader and the younger brother as the follower before and during the bombings, this case study categorizes and studies the causes of the Boston Marathon bombings at individual, group, and international levels through a special concentration on Tamerlan’s motivation, source of inspiration, activities, and purpose.

At the individual level, investigations show that the causes of the Boston Marathon bombings were rooted in Tamerlan’s turbulent personal life, the collapse of his family, and his successive failures. ⁶² Tamerlan linked these troubles and failures to the domination of his native land, Chechnya, by a non-Muslim force, which had led to the migration of his family and coreligionists abroad. This perception of life transformed Tamerlan’s belief system from a “relaxed Islam,” practiced in Muslim territories of the former Soviet Union, to an extreme Islamism. ⁶³ The process of Tamerlan’s transformation and behavioural change toward jihadism is also interconnected to factors at the group and international levels.

At the group level, Tamerlan was deeply influenced and radicalized by al-Qaeda’s jihadi Salafism. Before the bombings, he mostly accessed jihadi Salafi material, including motivating texts and videos, through the Internet and Chat Rooms. Searching the Internet for websites associated with Islamist groups in the Caucasus became his routine activity in the early 2010s. ⁶⁴ At this time, he not only read and watched the material but also made comments about them, presenting his sympathy to the global jihadist movement. In a Facebook status, for instance, he linked to an article and commented that the United States’ leadership was in an, “all-out war against Islam.” ⁶⁵ Likewise, texts, photographs, and videos found in Tamerlan and his wife’s computers show the bomber’s deep reliance on jihadi Salafism and his intense commitment to al-Qaeda’s jihadist project. ⁶⁶ Access to the jihadi Salafist material prepared Tamerlan to become an extremist with strong views against policies of the US and its allies in the Islamic world. For example, he did not approve of, the then, President Barack Obama’s use of drones in conflicts in Islamic countries and described the action as a dimension of American expansive foreign policy. ⁶⁷ As one of his friends, Don Larking, stated: “He [Tamerlan] felt the US should not get involved in other people’s affairs and should stick to its own business. He did not like the country’s involvement in Afghanistan and Iraq at all.” ⁶⁸

While accessing the jihadi material through the Internet was a significant factor in Tamerlan’s radicalization, a determinant cause of the Boston Marathon bombings was his trip to Russia between January and July 2012. This event connects the group-level factors to causes at the international level. During this trip, Tamerlan allegedly witnessed the, “Muslims revival,” in southern Russia and made contacts with jihadists in Dagestan. ⁶⁹ Upon his return from Russia, Tamerlan changed fundamentally. He grew a beard, took an extremist Islamist tone, criticized non-Muslims’ involvement in Muslim countries, and invited some family members to Islamism. ⁷⁰ Moreover, his, “anger over America’s foreign policy in Afghanistan and Iraq,” dramatically increased in this period. ⁷¹ At this point, the bomber was pushed to the practical stage of preparation for the Boston Marathon bombings.

Taken together, while the Boston Marathon bombings were influenced by factors at all three levels of analysis, evidence shows that causes at the group and international levels played a more critical role than factors at the individual level. In this context, Tamerlan’s commitment to jihadi Salafism and his Salafist interpretation of international politics in the Islamic world provided the bombing’s determinant causes. The determinacy of a particular cause, the complexity of causal relationships, and the causal interconnections in the Boston Marathon bombings and other cases are explained through a cross-level analysis in the following section.

A cross-level analysis: the role of willingness and opportunity

The HJV is not only the outcome of causes at separate levels of analysis, as discussed above, but it is also influenced by the interaction and interdependence of those causes in a cross-level context. ⁷² Thus, the levels-of-analysis framework explains not only a separate cause–effect relationship at every single level but also the interaction and mutual effects of those causes in the evolution of each case. This formulation explains the theoretical linkages among various causes within the contexts of willingness and opportunity. ⁷³

Within this context, causes related to willingness (actor-oriented variables) are first distinguished from causes related to opportunity (structural variables). Next, it is emphasized that variables belonging to the two categories are interrelated and mutually interactive. Their interconnection influences both the causal forces and their outcomes. ⁷⁴ Thus, willingness to act at one level is influenced by the opportunity provided at the other level, and, likewise, the opportunity at one level could be affected by the willingness for action at the other level. ⁷⁵ Concerning the root causes of HJV, this formulation means that a potential individual’s personal willingness to conduct jihadist violence (at the first level) is interrelated to the opportunity and motivation provided by jihadi Salafism as a group ideology (at the second level). Likewise, the group dynamism and ideology are affected, first, by the willingness of the individual jihadis for action at the first level and by the opportunity and abilities provided at the third or structural level. Concerning this paper, while each case is explained by causes at separate levels of analysis, the interplay and interdependence of those causes in a cross-level context are also significant in explaining each case.

In the three case studies, every individual jihadist indicated a willingness to contribute to something bigger than themselves (i.e., global jihad at the first level), and their personal choice to act as a violent agent was simultaneously influenced by the jihadi Salafi ideology and the major jihadi organizations’ propaganda at the second level. Likewise, while jihadi Salafism at the second level of analysis provided the individual jihadists with religious justification to act violently, the way they approached jihadi Salafism was influenced by the political and international environment produced in the post-9/11 context. Thus, the three case studies indicate that causes belonging to every level of analysis had not only direct but also interconnected impact on the outcome.

In the London bombings, for example, while both the decision-makers’ willingness to utilize violence and the opportunity to initiate a decision existed at all three levels of analysis, the outcome was also influenced by the interaction of those causes. Initially, the four bombers had a personal willingness to contribute to al-Qaeda’s global jihadism by conducting a terrorist act (at the individual level). Meanwhile, their preference for violence over other options was significantly influenced by the justifying opportunity provided by the jihadi Salafi material that they gained through social networks and the Internet (at the group level). Moreover, their personal decision and the interpretation of the choice at the individual and group levels were influenced by the post-9/11 international and political environment and the British government’s engagement in the invasion of Afghanistan and occupation of Iraq. In this international environment, the London bombers sought to put pressure on the British government to end this engagement. The bombers believed that the only option to achieve this goal was participation in al-Qaeda’s global jihadism. Thus, the interaction of factors related to both willingness and opportunity not only led to the London bombings but also influenced and reshaped one another throughout the evolution of the case.

The second case study, the Toronto 18 Plot, was similarly influenced, on the one hand, by both the willingness of actors at the individual level and the opportunity provided at the group and international levels and, on the other hand, by the interaction of those causes. The two ringleaders of the plot were initially willing to utilize violence in their hometown because they were dissatisfied with the international environment, “related to the suffering of Muslims in conflicts around the world.” ⁷⁶ Thus, two levels interacted: willingness to choose violence at the individual level; and the structurally engendered opportunities to initiate the decision at an international level. Meanwhile, the personal decision at the first level and reaction to international politics at the third level was influenced and justified by the jihadi Salafist material at the second level. Thus, as the case evolved, the bombers’ personal choice and reaction to the international environment at the individual and international levels, respectively, interacted with jihadi Salafi ideology at the group level. The interaction between factors of willingness and opportunity caused the Toronto 18 Plot to evolve to its highest stage before it was thwarted by the Canadian government.

The same model applies to the Boston Marathon bombings. The study of the bombing’s mastermind, Tamerlan, shows that three factors together generated the case: his willingness to act violently at the individual level; his choice to employ available capabilities at the group level; and his reaction to the broader international politics, particularly the American post-9/11 policy in Iraq and Afghanistan. The evolution of the Boston bombings, then, was the outcome of interaction and mutual effects of factors belonging to both willingness and opportunity. Affected by his failures and troubles, Tamerlan was personally willing to respond violently to the failures he was facing in the United States. Although he initially connected his failures to a broader problem—the threat, a non-Muslim force, Russia, was posing to his native land, Chechnya—his choice of violence in the United States was influenced by a new opportunity provided by group-level jihadi Salafi ideology and the post-9/11 international environment. Access to jihadi Salafist material mostly through the Internet converted the personally dissatisfied Tamerlan into a jihadi Salafist who was prepared to join al-Qaeda’s global campaign. Moreover, while the opportunity for Tamerlan’s violent action was present in the post-9/11 international context, it was exploited by his willingness at the individual level and interpreted by the jihadi Salafi ideology at the group level. These factors simultaneously led him to choose a specific course of action. ⁷⁷ The Boston Marathon bombings were materialized as a result of such cross-level, causal interactions.

Conclusion

This paper uses the levels of analysis framework to categorize and investigate the causes of HJV at individual, group, and international levels of analysis. I have argued that applying the levels of analysis framework to the study of HJV provides a multi-level and transnational context for the study of an international security problem that is conventionally examined through randomly selected criteria, mostly in national frameworks. This article is an effort to provide a broader image of HJV by applying a theoretical framework from the field of IR to study a problem belonging to the field of political violence.

The three case studies indicate that HJV is the outcome of a series of separate and yet interconnected causes at individual, group, and international levels of analysis. These case studies indicate that personal motivation to participate in the global jihad and the influence of the jihadi Salafi ideology are decisive for an HJV to emerge. Besides the two individual- and group-level factors, the post-9/11 international environment, particularly Western countries’ military policies in the Islamic world, also provides the root causes of HJV in the West. These factors connect the three case studies of this research as identical phenomena and, meanwhile, link them to other similar cases. Thus, with a special concentration on major aspects of HJV, the three case studies capture descriptive features of this phenomenon. These cases also represent HJV in three major North American and West European countries and, therefore, they provide a representative image of the problem in a transatlantic context.

Both the analytical framework developed in this paper and the case studies contribute to both academic and policy debates on HJV. Concerning the academic debate, this article contributes to the literature by bringing the IR levels of analysis literature into conversation with the radicalization to violence literature. In this regard, the paper introduces a new analytical framework to the study of HJV. This new framework helps categorize and explain the root causes of this security problem from micro to macro levels. Moreover, the three case studies, through the lens of levels of analysis, add new insight into the study of the causes of HJV, and the analytical framework developed in this paper has possible implications for studying more cases. As such, it seeks to provide a pre-theoretical basis for a broader debate on the causes of this global security problem.

Concerning policy, governments and policymakers have largely invested in measures from different national contexts to tackle HJV. This domestic-oriented approach has proven to be crucial in developing local solutions to a problem that, to a great extent, is individualized and localized. However, given the transnational nature of the jihadi campaign and the jihadi Salafi ideology, HJV is also global in nature and function. Therefore, since the emergence of HJV, there have also been effective examples of transatlantic cooperation for countering this transnational problem. This paper’s multi-level and transnational approach to the study of HJV further highlights the resilient and cross-national characteristics of HJV and, therefore, seeks to introduce an analytical framework that contributes to transatlantic ties and efforts on a security problem haunting the West beyond sovereign boundaries since 9/11. Moreover, the paper’s emphasis on the link between Western countries’ post-9/11 foreign policies in the Islamic world and the rise of HJV highlights how anger over those policies produced violent responses in various forms of HJV. Thus, the link between Western foreign and military policies in Islamic countries and HJV as a response to those policies suggests that Western governments should reflect more thoroughly on the impact of their foreign actions. Such reflection may prevent the emergence of similar problems at home. Overall, taking the complex, resilient, reactive, and, yet, transnational nature of HJV into consideration, this paper studies the problem as an outcome of a series of causes at multiple levels in different countries on both sides of the Atlantic. By introducing a multi-level analytical framework to the study of HJV, this paper provides a pre-theoretical basis for further and broader debates on the causes of this global security problem.