Over 20 years after the US military campaign in Afghanistan and Iraq and the 9/11 events of 2001, most European experts and analysts believe that terrorist activity in Europe has decreased and that terrorism is no longer as powerful as it was in the first decade of the twenty-first century or post-ISIS. However, the recent decline in terrorist activity in Europe does not imply the end of terrorist groups or their threats. There are still sleeper cells plotting and awaiting an opportunity to return to the field. 

Sleeper Cells 
The proliferation of terrorist groups and control over various areas in the Middle East, Central Asia, and Sub-Saharan Africa helped them create sleeper cells and a network of interrelations in some Western States. These groups spread in some major European countries and managed to cooperate with entities and individuals associated with organized crime groups there. This helped the cells to carry out terrorist operations that shook the European society and put the political, security, and military authorities in a constant state of alert and mobilization. Among the deadliest operations carried out in Europe are the Madrid bombings of 2004 that targeted commuter trains in Madrid, killing around 200 people and injuring 1755. Even though the mastermind and his aides were expatriates or agents that infiltrated the country shortly before the events, some of those involved in the plotting and implementation were directly involved in the Spanish society, and it was difficult to predict their subversive intentions.

The Past is Past
Years have passed since the Madrid bombings and the attacks in London, Paris, and Brussels; European communities appear to have turned over a new leaf. They are no longer eager to host events in honor of the victims of such atrocious crimes. Although terrorist activity and the menacing political extremism were top priority for the European community ten years ago, surveys show that Europeans are now more concerned over exorbitant prices and the implications of the economic inflation, the Russia-Ukraine war, irregular migration, and global warming.

A dissertation examined at the Autonomous University of Madrid in 2022 on the recruitment methods of ISIS and other terrorist organizations argues that the former’s recruitment in European countries relied on advanced propaganda and promotion based on three main pillars: first, finding new elements who meet their requirements; second, monitoring new elements and trying to communicate with them; third, brainwashing them and convincing them of ISIS ideologies and principles, then turning them into extremists ready to operate unhesitatingly upon command. Contrary to what some analysts may think, recruitment does not necessarily rely on having extremist views, but may itself cause such extremism. Terrorist organizations, meanwhile, benefit from the state of turmoil their targets live in to transform them into terrorists, suicide bombers, and fighters.

Social Movements
The dissertation asserts the importance of analyzing recruitment in Europe based on the Social Movement Theory, which is an interdisciplinary study that seeks to explain why such phenomena occur by examining the ideological, dynamic, and political tendencies in society and not just observing single cases out of social context and classifying them as deviant or exceptional. Accordingly, several discussions following the Madrid bombings and the following attacks in other European capitals showed that members of terrorist groups in Europe are ones who hated their societies and could not coexist there, as well as migrants who felt alienated from their environments. 

Furthermore, security and press investigations, as well as scholarly studies, confirm that many of those who approached or joined terrorist groups were religious to varying degrees and did not come from marginalized, impoverished, excluded, or poorly educated segments, but rather the opposite. As such, they do not always meet pre-defined criteria. ISIS or al-Qaeda recruits in Yemen, Iraq, Syria, Afghanistan, and Sahel countries are not the same as those joining extremist groups in Europe. 

The first category comprises veterans discharged from the army like in Iraq, destitute people displaced by armed conflicts like in Syria, or impoverished people who do not have enough awareness that they are lured by money to commit violence and terrorism like in Sahel countries. In addition, some countries cannot extend their control over all their lands and adopt exclusionary, oppressive, and violent practices against their citizens. Thus, joining terrorist groups there is often meant to combat those malpractices.

Recruitment in Europe
Despite the large numbers recruited in impoverished European suburbs full of immigrants and lacking social services, a large percentage of criminals were radicalized in prisons by fundamentalist activists. Meanwhile, others from educated classes believe in the importance of combat and have personal and social traits that push them towards isolation rather than integration into families and societies. This should be put into consideration by security agencies and counter-terrorism bodies. In addition, another phenomenon worth examining is that a large percentage of those who are skilled in managing modern technologies, information, internet networks, and social media are recruits in Western countries. They are generously paid by terrorist groups, even more than their peers who work in government entities or the private sector.  

What drives them to collaborate with extremist groups is not money, but ideological motivations and, in some cases, a desire for vengeance from European communities for alleged workplace maltreatment of them and their families, as well as deprivation of high-ranking positions in State management.

The involvement of these calibers with terrorist organizations aided in the development of their electronic and information mechanisms, the deep web, and communicating with, influencing, and recruiting certain young segments in Europe on social media platforms such as Twitter, Facebook, and Instagram. 

The testimonies of some extremists in these terrorist groups expressed their dismay over the discrimination between them and others in the IT departments who earn high bonuses, since they are allegedly more capable of attracting more recruits, resulting in more media influence on the world in general and Europe in particular. 

Different Motives
Given the different motives to join extremist groups, examining the issue must address the various facets of the problem, including the ideological, intellectual, economic, political, and social ones. Therefore, the psychological concept “framing”; i.e., setting up group activities, is relevant, whereby it is important to focus on contexts that provide a solid blueprint for meanings, beliefs, and general stances that justify a certain collective plan. This is in addition to a specialized discourse that constantly aims to validate actions no matter how seemingly brutal and inhumane from afar. 

Guidance groups in terrorist cells determine the striking topics for the target population group first, then create an ideological system that comprises certain steps to address a perceived problem and find the ideological justifications to take decisive action to solve that problem.

To be sure, terrorist organizations’ guidance and propaganda have had some success in creating problems that make European citizens believe it is necessary to take a set of measures, even if they result in terrorist action. “Framing” succeeds when an individual is involved in the final stage, which is the unconditional willingness to contribute to the final decisive action.

We can only comprehend the implications of framing by first comprehending the Social Movement Theory, particularly in terms of recruitment and mobilization, because these parameters constantly update the «perpetual thinking industry» and work according to a propaganda plan that creates slogans to promote fundamental visions to supporters. This process is manifested in ISIS’ plans to polarize European youths to its bases in Syria and Iraq in the second decade of the 21st century. Such terrorist organizations promise to provide a pure religious environment free from hypocrisy and blasphemy. Such promises are only tempting by virtue of the effective framing plans. 

Furthermore, propaganda strategies included temptations to live in a so-called caliphate that is better than the homeland. Despite the severity of wars and economic and social crises in remote areas, framing provided terrorist organizations with an ideal environment in which to achieve their primary goal. Thus, it was framing that enticed hundreds of European young people to join such extremist groups to perform various functions such as fighting, covert propaganda, and unofficial websites and social media management, by providing them with motives, needs, and solutions through messaging and discourse that are simple to understand and that do not require much thought. These frames are flexible, changeable, and scalable, but anchored on an estrangement between «us» and «them». 

It can be concluded that previously existing terrorist plans can resurface and rethreaten the European community, even if they do not appear to exist or have a strong influence today. To avoid passing these horrors on to the European community, governments must consider the past implications of terrorist crimes, make every effort to prevent them from happening again in the future, and consider the strategic mistakes that resulted in power vacuums and turmoil in some States, such as Afghanistan, Iraq, and Syria.

Furthermore, security and civil and social institutions must monitor any suspicious activity by terrorist sleeper cells and coordinate with other States to stop them before they become full-fledged threats.