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This online-only paper was written on the occasion of the 25th anniversary of the terrorist attacks of September 11. It presents some of the author's ideas about the enduring relevance of terrorism today, including references to related work. This paper may occasionally be updated and revised. Originally posted on August 28, 2026.
Please cite as: Deflem, Mathieu. 2026. "9/11 at 25: Reflections on Terrorism Today." Online paper, first posted online August 28, 2026, at Deflem.blogspot.com.
After and because of the events of September 11, 2001, terrorism moved to the center of public and intellectual attention. Now, as we are 25 years later, it can be noted, however, that terrorism no longer occupies the centrality in thought and culture it once had. This silence of terrorism must be described as at times bewildering and disturbing. How and why this change has occurred informs these reflections I post on the occasion of the 25th anniversary of 9/11. This paper thereby relies on, and extends from, my published work on terrorism and counterterrorism. Embedded links lead to writings that, for those who are interested, explain in more detail and at greater length.
Thinking Terrorism
To be sure, to some extent there is nothing new. It has after all often been remarked that terrorism would be difficult to define. But it remains true that such a statement is not useful because it overlooks the fact that every category of action and thought has to be defined and that definitions rarely, if ever, meet with universal agreement. Instead, it should be observed that terrorism is defined differently in different contexts. Thus, terrorism is a concept as well as a legal category, a political construct, as well as a normative and often contested idea.
Sociologically, terrorism can be defined from the viewpoint of the study of social control as the use of illegitimate means for political-ideological purposes. Terrorism typically involves violent tactics indiscriminately aimed at civilians on a relatively massive scale, much like is the case in war. Yet, terrorism is different from warfare in that it exists outside of, and purposely operates against, the principles of war as regulated in the international community of nations. Acts of terrorism are violent and purposely destructive, politically oriented and ideologically motivated, ranging from specific goals formulated in terms of political nation-states to aims related to certain peoples and groups.
The instilling of fear (terror) is an important immediate objective of terrorism. Historically, the term terrorism originated during the aftermath of the French Revolution, when the French National Assembly in 1793 decreed a mass mobilization of all able-bodied men in order to secure the republic and thwart off the internal and external enemies of the revolution. During the resulting ‘Reign of Terror,’ several tens of thousands of people, most of them ordinary workers and peasants, were massacred as enemies of the people.
Counterterrorism strategies exist at many levels. Politically, counterterrorism measures have typically developed in a piecemeal fashion to focus, initially not on terrorism as such, but on specific issues commonly associated with terrorist activity, such as hijackings and bombings. In the United States, the Act to Combat International Terrorism and the Omnibus Anti-Terrorism Act were passed during the administration of Ronald Reagan in the 1980s. More legal changes have come in the wake of the events of 9/11, specifically the USA PATRIOT Act and its related policies. Similar initiatives have been developed in other nations and by international organizations, such as the United Nations.
Counterterrorism can be analyzed as a matter of social control, including the mechanisms and institutions that define and respond to terrorism. The reality of terrorism therefore includes its construction, and the application thereof, by various agents of social control, including police. Terrorism will typically be applied rather eagerly by relevant institutions of law and law enforcement, but there are also important variations.
Striking is the manner in which concepts of terrorism by various agents and institutions of social control can contract or expand its meaning and reach. In the United Kingdom, terrorism legally requires a political or ideological motive, no matter how many victims are involved. In the United States, by contrast, it is possible for terrorism charges to be filed even when a criminal act lacks an ideological justification but is indiscriminately meant to instill fear.
When then 17-year old Axel Rudakubana was charged with killing three young girls, aged six, seven, and nine, and wounding eight other children and two adults in a stabbing rampage at a Taylor Swift-themed dance class in Southport, England on July 29, 2024, he was trialed (and eventually convicted) on three counts of murder and ten counts of attempted murder but not on terrorism charges. Despite the fact that the teenager had sought to “carry out mass murder of innocent, happy young girls” and had thereby relied on an al-Qaeda manual for his methods, prosecutors argued that his motives were not related “to any particular political or religious ideology… His only purpose was to kill” (New York Times, January 30, 2025). By contrast, when 42-year old Bradford James Gille was accused of having stabbed and wounded eleven people at a Walmart near Traverse City, Michigan on July 26, 2025, he was charged with terrorism, along with multiple counts of attempted murder. Even though “a motive for the attack remained undetermined,” the prosecuting attorney in the case argued that the attack was deliberately meant “to bring fear and destruction to a community as a whole, rather than to harm specific individuals” (New York Times, July 27, 2025).
September 11 and Since
The events of September 11, 2001 were a critical moment in the history of terrorism in the United States and around the world. Since 9/11, terrorism has remained a disturbing reality, even though it is not always recognized as such, which, given the inherent violence of terrorism, makes the matter all the more puzzling. During the 1990s, terrorism had become increasingly consequential for the United States. The World Trade Center bombing on February 26, 1993 killed 6 and injured more than 1,000. The Oklahoma City Bombing on April 19, 1995 killed 168, including 19 children, and wounded almost 700. On August 7, 1998, simultaneous attacks on the U.S. embassies in Kenya and Tanzania killed 224 people and injured more than 4,000. The bombing of the USS Cole navy ship on October 12, 2000 killed 17 and injured 39. Then, the al-Qaeda terrorist attacks of September 11, 2001 killed 2,977 people from 90 nations. The tragedy was followed by anthrax letters being sent to media and politicians in September and October 2001, which killed 5 people. On December 22, 2001, an al-Qaeda operative failed to detonate a shoe bomb aboard a flight from Paris to Miami. The European continent was also hit with jihadist al-Qaeda bombings, most notably in Madrid on March 11, 2004, when 193 people were killed and more than 2,000 injured, and in London on July 7, 2005, when 52 people were killed and more than 700 injured.
The United States has experienced continued terrorist incidents over the past decades. Among the most noteworthy examples, on November 5, 2009, an extremist killed 13 and wounded 29 in a mass shooting at the Fort Hood military base. On August 5, 2012, a neo-Nazi killed 6 people and injured 3 at a Sikh temple in Wisconsin. Terrorism in the United States hit again most forcefully on April 15, 2013, when two extremists inspired by al-Qaeda committed a bombing at the Boston Marathon that killed 3 people and wounded an additional 264. One of the perpetrators was killed during a shootout with police, while the other, his younger brother, is currently on death row.
Other attacks in the U.S. since then include multiple incidents, only a few of which can be mentioned here. On June 17, 2015, a 21-year old white supremacist killed 9 African-American churchgoers in Charleston. On July 16, 2015, an extremist killed 4 U.S. Marines and a Navy sailor in Chattanooga, Tennessee. On December 2, 2015, a married couple inspired by foreign terrorist groups engaged in a mass shooting at the Inland Regional Center in San Bernardino, California, killing 14 and injuring 24. On June 12, 2016, an American-born man who had pledged allegiance to ISIS (the Islamic State of Iraq and Syria) killed 49 people and wounded 53 in a shooting spree at gay nightclub Pulse in Orlando.
In the 2010s, but thereafter as well, there was a wave of terrorist attacks in which vehicles were used as a weapon. Some of these so-called ‘(vehicle-)ramming attacks’ took place in the United States. Notably, on October 31, 2017, 8 people were killed and almost a dozen injured when an ISIS-inspired extremist drove a truck down a bicycle path in New York City. On the night of January 1, 2025, another ISIS-inspired man drove a truck into partygoers on Bourbon Street, New Orleans, killing 14 and injuring 57 people.
In more recent years, terrorism has remained a concern in the U.S., motivated by a wide range of ideological beliefs. The occasionally voiced notion that white supremacy or any other one ideology would pose the biggest terror threat in the United States today is unsupported by evidence. Instead, contemporary terrorism in the U.S. takes on many forms representing multiple ideologies (see overview.) Some examples will highlight the continued reality of terrorism in the U.S. in the past decade. On October 27, 2018, a man motivated by Jew-hatred killed 11 people at the Tree of Life synagogue in Pittsburgh, a crime for which he later received the death penalty. On August 3, 2019, 23 people were killed in El Paso, TX in a mass shooting by a white nationalist in a Walmart store. On December 6, 2019, an al-Qaeda inspired gunman killed 3 sailors on a Navy base in Pensacola, FL. On December 10, 2019, two shooters killed 3 people in a Kosher grocery store in Jersey City, NJ. They were charged as terrorists because the attacks were motivated by antisemitic and anti-police beliefs.
On May 14, 2022, an 18-year old shot and killed 10 people in a supermarket in Buffalo and was charged with hate-motivated (anti-Black) domestic terrorism. For their involvement in violence against police in Atlanta on January 21, 2023, six people were charged with domestic terrorism. In December 2024, a George Mason University student from Egypt was arrested for a planned terrorist attack on the Israeli embassy in New York. On May 21, 2025, a man killed a soon-to-be engaged Jewish couple who worked at the Israeli embassy in Washington, DC. On July 4, 2025, a plot targeted the Prairieland ICE facility in Alvarado, Texas, for which 8 offenders, alleged to be members of an Antifa cell, were found guilty on terrorism charges in March 2026.
Among the incidents just this year, on January 2, 2026, the FBI announced it had thwarted a planned New Year’s Eve terror attack, involving an ISIS-inspired 18-year old who planned a knife attack against random people in North Carolina in order to “do jihad”. In March 2026, self-professed ISIS supporters, teenagers Emir Balat and Ibrahim Kayumi, attempted to detonate two improvised explosive devices amongst protesters at the New York City mayoral mansion. They were subsequently indicted on federal terrorism charges. On August 20, 2026, the FBI arrested a woman, who had pledged allegiance to ISIS and celebrated 9/11, for plotting to bomb the state Capitol in Albany, NY.
Counterterrorism 9/11
The relevant contexts of terrorism and counterterrorism include historical changes and continuities, political and legal developments, the institutional context of relevant agencies, and local, national, global, and other jurisdictional issues. Most important among the general empirical trend in these developments is the general observation that the impact of 9/11 was part of a longer and, in some and other ways, still ongoing process. The World Trade Center bombing on February 26, 1993 and the Oklahoma City Bombing on April 19, 1995 influenced passage of the Antiterrorism and Effective Death Penalty Act in 1996 during the Presidency of Bill Clinton. When President George W. Bush was confronted with 9/11, ideas of commissions set up under Clinton were relied upon to create the Office of Homeland Security, which in 2002 turned into a full-fledged new Department of Homeland Security (DHS). Since 2020, DHS has grown to more than 240,000 employees, including various agents as well as support staff. The Department’s budget rose from about $50 billion in 2012 to $52 billion in 2022, $56 billion in 2023, and a request of $62 billion for 2025.
Legally and, relatedly, politically, counterterrorism in the U.S. has mostly been framed in terms of the USA Patriot Act and the (Global) War on Terror, leading to concerns related to civil and constitutional rights and the appropriateness of military force. The policing of terrorism, however, has taken an independent path based on professional expertise of the goals and means of counterterrorism policing. Focused on terrorism as criminal conduct, police actions are primarily guided by efficiency considerations. Thus, the Federal Bureau of Investigation (FBI) in the State Department relies on Joint Terrorism Task Forces (JTTF). At present, there are about 200 such local JTTFs, some 65 of which were created after September 11. In the Department of Homeland Security, the largest investigative force is Immigration and Customs Enforcement (ICE), which oversees more than 20,000 law enforcement and support personnel in more than 400 offices in the U.S. and around the world. From the beginning,
As in the United States, police institutions in other nations have also, albeit in different way, been involved in counterterrorism. Among the examples are nations that have longstanding local terrorism problems, such as Ireland, Spain, and Israel. In some countries, terrorism has declined, while in others it has remained of great relevance. In Israel, the situation is such that a permanent state of emergency has been said to exist, which necessitates heightened alert and special operations, such as by means of covert actions (e.g., the mistaravim units of the YAMAS) and military operations (e.g., the war in Gaza after October 7). My research has investigated aspects hereof following research in Israel in 2004 and a follow-up study in October 2024, a year after the Hamas atrocities, which included a visit to the Gaza Envelope. (see video presentation).
Despite local and regional variations, the events of September 11 have greatly influenced counterterrorism efforts. Terrorism has in the post-9/11 era for several decades served as a symbol that unites nations, even when they otherwise differ from one another in political, legal, cultural, and other relevant respects. Yet, while terrorism instigated much international cooperation among police right after September 11, there have been serious ebbs and flows of cooperation since. The case of Interpol is sadly alarming, for Interpol is today not nearly as involved with counterterrorism as are specialized police forces within individual countries and as was Interpol in the immediate post-9/11 years. Strikingly, also, Interpol has taken no action regarding the attacks on October 7 by the Islamic Resistance Movement Hamas, despite the international dimensions of the mass atrocity and the call of some private groups, such as the Simon Wiesenthal Centre, to issue Red Notices against Hamas leaders.
Terrorism Globally
Terrorism has since 9/11 remained a reality in many nations across the world. A global picture is difficult to sketch in brief, but just a few, very selective illustrations will clarify some of the dynamics of terrorism as a global phenomenon.
As mentioned, since the 2010s there have been various vehicle-ramming attacks, which began as coordinated actions and have since lasted in less organized but nonetheless lethal and terror-inducing form. The tactic of using trucks as “mowing machines” against pedestrians was first advocated in an al-Qaeda publication of 2010, after which the method was adopted by other jihadist extremist groups as well. Between 2014 and 2017, there were at least 17 attacks whereby vehicles were used to drive into people, killing a total of 173 people and injuring 667. Most notorious is the truck attack in Nice, France on July 14, 2016 (Bastille Day), when a man drove a cargo truck into spectators, killing 86 people and injuring over 400 others. ISIS claimed responsibility for the attack. Other notable cases in 2016-2017 include ramming attacks at a Christmas market in Berlin, Germany in December 2016, killing 12 people; against pedestrians in London and Westminster, UK in March and June of 2017, killing a total of 13 and injuring more than 100 people; on a shopping street in Stockholm, Sweden in April 2017, killing 5 people; and against crowds in Barcelona and Cambrils, Spain in August 2017, whereby 16 people were killed. In the U.S., an ISIS-inspired attack using a truck down a bicycle path in New York City in October 2017 killed 8 people.
During the 2020s, these ramming attacks diversified (see list), leading to a total of up to 1,100 deaths and 3,500 injured globally. In November 2021, a man drove an SUV through a Christmas parade in Waukesha, Wisconsin, killing 6 people and injuring 62. Likewise not ideologically motivated but nonetheless relying on the terrorism-related tactic, a driver rammed an SUV into people near a sports center in Zhuhai, China in November 2024, causing 35 deaths. Other cases remain driven by ideological motivations related to jihadist extremism. Among the examples, perpetrators claiming allegiance to ISIS drove vehicles into police officers in Colombes, France in April 2020 and into pedestrians and cyclists in Oléron, France in November 2025, injuring several. Most recently, on July 26, 2026, an ISIS sympathizer (who had earlier been convicted on terrorism-related charges) drove a minivan into a pride parade in Berlin, killing a 65-year old woman and injuring 16.
Popular music concerts are peculiarly vulnerable to terrorist threats because they concentrate many people in an atmosphere of fun and entertainment (see De Cauwer, H. et al. 2023). Among the examples, on November 13, 2015, 90 fans were killed at the Bataclan venue in Paris as part of a larger series of ISIS attacks that killed 130 people. On May 22, 2017, a jihadist killed 22 and injured over a 1,000 people after a concert by Ariana Grande at Manchester Arena. On March 22, 2024, ISIS-affiliated terrorists killed 145 and wounded 551 people at a sold-out rock show in Crocus City Hall near Moscow, Russia. In August 2024, three planned Taylor Swift concerts in Vienna, Austria were canceled after police foiled a terrorist attack planned by two teenagers inspired by ISIS. In May 2025, Brazilian authorities thwarted a bomb attack that threatened Lady Gaga’s Mayhem concert on Copacabana Beach in Rio de Janeiro, Brazil.
The worst terror attack at a music festival occurred on October 7, 2023, when a total of 378 people attending the Nova Music Festival near kibbutz Re’im were murdered, and an additional 44 taken hostage, as part of the mass atrocity by the Islamic Resistance Movement Hamas against the nation of Israel. That fateful day Hamas forces murdered 1,195 people and took 251 hostage into Gaza (74 of which were later, or subsequently found to have been, murdered). The attack involved unspeakable acts of murder, torture, and sexual violence (Lamb 2025).
The tragic irony of the atrocity at Re'im taking place at a music event is aggravated by the fact that most of the festival attendants were relatively young people, many of them anti-war, leftist, and in favor of peaceful co-existence between Jews and Arabs. Like many of the civilians in the nearby kibbutz communities (who were likewise victimized on October 7), concertgoers who lived nearby engaged in friendly contacts with people from Gaza, such as by providing employment and medical assistance. Since October 7, these inter-community contacts have ceased, and attitudes towards conflict resolution have been adversely affected. Mental health concerns among surviving festivalgoers (such as PTSD) are likewise extreme. Some survivors of the Nova festival are reported to have committed suicide.
Social Control and the Poverty of Sociology
Corresponding to major sociological theory groups, social control is conceptualized to respond to, construct, and/or reproduce more than crime and/or deviance. Crime causation theories examine the causes of criminal behavior; crime construction perspectives focus on how crime is constructed out of deviance through various mechanisms of social control; and critical theories analyze the broader economic, political, and other societal implications of social control in society. Through the latter perspective, which has gained widespread dominance, the focus of sociological attention may go entirely to counterterrorism at the expense of any, even the slightest, consideration of the reality of terrorism.
Although the decline of terrorism as a concern among the public at large may be driven by a variety of factors, it is clear that academia plays an important role, especially given the ubiquity of higher education today. Because of certain problematic developments in social control at the dawn of the new millennium (e.g., high incarceration rates, alleged police misconduct, privacy and civil-liberty concerns following 9/11), social control in the early 21st century became a central focus of social-science scholarship. In this context, mention can be made of scholarly work on surveillance, mass incarceration, police violence, counterterrorism, and other dimensions of social control. These developments often also move the public at large and involve much debate, such as was witnessed with concerns over the rise of surveillance in the wake of domestic spying, anti-police protests during the COVID-19 pandemic, and other movements that have targeted criminal justice, such as ICE operations.
As a corollary to rising concerns over social control and counterterrorism, there has been a decrease of popular concern over terrorism. Based on opinion surveys, such as Gallup and Pew Research Center, Americans have since 9/11 decreasingly perceived of terrorism as an important problem. Gallup data show that terrorism was seen as an important problem by 46% of respondents in October 2001, a number than went down to 10% in January 2003 and to just 1% in September 2010. As seen from the numbers below, this trend has continued until at least 2021.
While terrorism has recently been seen as less of a big concern (among both Republican and Democrat citizens), trust in the government has generally declined in the years since September 11 and, instead, growing concerns have been expressed over counterterrorism. For instance, data show that the number of people who think that the U.S. government should take necessary steps against terrorism even if civil liberties were violated declined from 47% in 2002 to 25% in 2011. As indicated above, this trend has generally continued since then. Besides the culture of privacy what has also contributed to negative sentiments against surveillance (and policing) is the uninformed ideological direction that has occurred among some academics, such as in ‘surveillance studies’ and so-called ‘social justice’ perspectives.
Additionally, there are also situational factors (such as the Boston Marathon bombing in 2013, video-taped fatal police arrests during and since the COVID-19 pandemic, and ICE operations against illegal immigrants in 2025 and 2026) that influence how people feel about surveillance, counterterrorism, and policing. Likewise, terrorism can re-emerge as an issue in the wake of high-profile terrorist incidents. But one may wonder, would it really be necessary for another attack as grave and lethal as 9/11 to take place now in order for the reality of terrorism to be understood (see, e.g, ING; CBC)? Worse yet, it is not without cause to fear that even an incident as deadly as the al-Qaeda attacks of September 11 were it to happen today would not be able to alter current thinking that terrorism would not be a reality that can, accurately and rightly, be so named.
