How should we face terrorism in the age of home-grown and lone offenders?

Not every indiscriminate killing or irrational act can be called terrorism

When we watch the news, we see incidents referred to as terrorism occurring somewhere in the world. What is surprisingly little known, however, is that there is no single, academically and practically agreed upon definition of the word “terrorism.”

However, from an academic point of view, at least three fundamental elements are considered necessary to be called terrorism. First, it has a political motive. Second, it does not merely attack the target but aims to spread fear throughout society. And third, it uses illegal violence or threat of violence to achieve that goal. These three are considered the minimum requirements for an academic definition of terrorism.

From this perspective, the biggest difference between a terrorist organization and a gang, or murder in general, would be the presence of a political motive. Indiscriminate killing and injury are often thought to be terrorism, but this is not necessarily considered a requirement of terrorism.

For example, the shooting of former Prime Minister Shinzo Abe in 2022 could fall under terrorism from an academic point of view if the motives for the act included political intentions (* This point is not necessarily clear at the time of writing, December 2025.) On the other hand, the Kyoto Animation arson murder case in 2019 resulted in many victims, but no political motive was confirmed. Therefore, it is understood not to constitute terrorism in an academic sense.

This ambiguity of definition often leads to confusion in discussions of terrorism. For example, when the Islamic group Hamas attacked Israel in 2022, there was some debate about whether to call it terrorism.

By applying the three requirements mentioned above, Hamas’s acts are understood to be classifiable as terrorism. However, some journalists and commentators add a fourth requirement to the three aforementioned requirements of terrorism: it must be an act not based on justice or an immoral act. From these standpoints, some may understand that Hamas’s attack cannot immediately constitute terrorism, based on the view that it cannot be simply condemned when considering the historical background of the Gaza issue and the oppression by Israel.

However, when a value judgment such as “acts not based on justice” or “immoral acts” is added to the criteria for terrorism, the conclusion on whether it is terrorism can change depending on the viewpoint or factors such as values regarding the interpretation of justice and morals. This slows down discussions from the perspective of counterterrorism. For this reason, in academic discussions, quite a few take the position of refraining from including acts not based on justice and immoral acts in the definition of terrorism, that is, the position of separating value judgments from the definition.

Regardless of which position you take, when discussing terrorism, clarifying participants’ understanding of the definition of terrorism beforehand will help avoid confusion in the discussion.

Rising home-grown and lone offenders

What is the current state of terrorism? As a matter of fact, in recent years, the number of terrorist incidents and harm caused in developed Western countries have been on the decline overall.

According to the Global Terrorism Index 2025 published by the Institute for Economics & Peace, an Australian think tank, the number of terrorist incidents in developed Western countries fell by about 30% in 2024 from their peak in 2017. Worldwide, most of the deaths caused by terrorism are concentrated in Pakistan, Iraq, Afghanistan, and the Sahel region of Africa. The percentage of such deaths in developed Western countries is less than 1%.

On the other hand, the form of terrorism itself in developed Western countries is changing. In the past, major terrorist attacks in developed Western countries, such as the attacks by Al Qaeda in the United States (2001) and the attacks by the Islamic State (ISIS) in Paris (2015), were often carried out by highly trained terrorist groups dispatched from overseas. In recent years, however, incidents involving “home-grown” terrorists and “lone offenders” have become more prominent.

Simply put, home-grown refers to terrorism that people originating from a country commit within that country. Meanwhile, a lone offender refers to a type of individual not affiliated with a specific organization carrying out terrorism alone. Many of the recent terrorist attacks in developed Western countries have been carried out by home-grown lone offenders.

Two major factors are believed to be behind this situation. The first factor is that, since 9/11, the international community as a whole has made progress in its efforts to prevent large-scale terrorism. As a result of countries tightening immigration controls at airports and borders and establishing systems to monitor terrorist organizations’ funding routes, it is considered significantly more difficult for foreign terrorist groups to infiltrate and launch large-scale attacks in developed Western countries.

The second factor is the development of the Internet, particularly social media. In the past, those who wanted to carry out terrorism often went to training camps of terrorist organizations in conflict zones such as Syria and Afghanistan to learn how to handle weapons and make explosives, as well as extremist ideology. However, terrorist groups now spread their ideological propaganda through social media and video sites, and information such as methods of making bombs is easily available. As a result, it is believed that more individuals living in developed Western countries are becoming independently influenced and committing acts without direct contact with foreign terrorist organizations.

Should we aim for zero terrorism or manage the risks posed by terrorism?

Home-grown lone offender terrorism is considered difficult to address within the conventional counterterrorism framework. Since they do not cross borders, immigration cannot stop them. In addition, as individuals acting independently, they lack trace of organized financial flows or communications and are difficult to detect in advance by means such as monitoring financial transactions or intercepting communications.

In the past era of organized terrorism, measures such as arresting and negotiating with the leaders to bring down the organization were considered effective to a certain extent. However, at present, many acts are committed on an individual basis, and such top-down disablement has become difficult. As a result, although the frequency and damage from large-scale terrorism is decreasing, completely preventing terrorist acts is likely becoming rather difficult.

As an analogy, it is like the average score on all achievement tests has gone up, but only some of the questions have become so difficult that almost no one gets a perfect score.

In the first place, there is also the fundamental question of what the objective or goal of counterterrorism should be. One approach is to set the goal of counterterrorism as foreseeing and preventing all terrorism and reducing damage to zero. This can be called a zero terrorism or zero risk approach. From this perspective, empowerment of security agencies can be considered as a means of achieving the policy goal. For example, strengthening abilities such as wiretapping and undercover investigation. (In this case, democratic control over security agencies may also be an issue in order to balance security and human rights.)

Another approach is to set the goal of counterterrorism measures not to completely prevent terrorism but to minimize various harm that terrorism poses on society as a whole. The premise of this position is that harm caused by terrorism is not necessarily limited to direct and physical harm (such as number of deaths and injuries from terrorist attacks) but also includes a wide range of “defects” caused to society by the fear spread by terrorism. For example, excessive fiscal spending, violation of human rights, and social fragmentation that counterterrorism measures by the government can cause are considered a part of such social harm. In this approach, the objective of counterterrorism measures is to minimize the total defects affecting society as a whole. This approach considers it important for society to continue to function calmly in the event of a terrorist attack without getting overly upset, in other words, to enhance social resilience.

While the former can be described as an approach aiming at zero terrorism or zero risk, the latter can be described as an approach aiming at managing the risks posed by terrorism. Ethically, the former is based on the idea of deontology, while the latter is based on the idea of utilitarianism. Broadly speaking, deontology is the idea that it is good to have a foundation of morals and values that everyone should follow. Utilitarianism, on the other hand, emphasizes maximizing the sum of the utilities of society as a whole, or achieving the greatest happiness for the greatest number. Neither of the two is necessarily the only absolutely correct answer. The former approach can be criticized for potentially undermining the interests of society as a whole. In contrast, the latter approach can be ethically criticized for tolerating certain sacrifices. The contrast between the two approaches may be similar to the debate over zero COVID versus coexistence with COVID during the COVID-19 pandemic.

For example, in the past, when a bomb threat against a local government was spread on social media, it was common to completely suspend its services (a zero terrorism or zero risk approach). However, in recent years, some local governments continue services as usual while strengthening security in cooperation with the police and disclosing information to the public. This may be an example of incorporating the concept of managing the risks posed by terrorism into actual administrative responses.

How should the will of the public be reflected in policy?

Neither of these two different approaches to counterterrorism is the absolutely correct answer. It can also be considered a matter of choosing values between deontology and utilitarianism. In a democratic country, it is desirable for the people themselves, as the sovereign, to make decisions based on their own values, and for such decisions to be appropriately reflected in policies through politicians who represent the people.

However, one notable point is that the police in charge of counterterrorism in Japan today have a system where swiftly reflecting the will of the public is not always easy.

In typical government ministries, such as Ministry of Finance and the Ministry of Education, Culture, Sports, Science and Technology, the head of the organization is the minister. Ministers are appointed by the prime minister and are in a position to bear the will of the public through elections. Therefore, they are responsible for swiftly indicating the direction of administrative management based on the will of the public, while being accountable to the public. This is a system design based on the idea of democratic accountability.

In contrast, the current Japanese police institutions at both the national and prefectural levels are under the control of the Public Safety Commission systems, which are collegial administrative bodies. This system was established after World War II to separate politics and the police to a certain extent, based on the lessons learned from the politicization of the police before and during the war, which was exploited to suppress free speech.

Such a system is considered superior in ensuring the political neutrality of police activities. But at the same time, the function of politics to swiftly determine the direction of police administration based on the will of the public, that is, the function of democratic accountability, is considered weaker than other administrative fields that employ a ministerial system. In other words, political neutrality and democratic accountability can be seen as a trade-off. Academically, one does not always take precedence over the other. It is generally thought that the former takes precedence when social values are stable, and the latter takes precedence when social values are diverse and fluid.

When considering modern counterterrorism measures, people themselves may need to think proactively about how to reflect the will of the public more effectively in policies, taking into account such institutional characteristics.

* The information contained herein is current as of August 2025.
* The contents of articles on Meiji.net are based on the personal ideas and opinions of the author and do not indicate the official opinion of Meiji University.
* I work to achieve SDGs related to the educational and research themes that I am currently engaged in.

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