The Military, Police, and the Rise of Terrorism in the United States

The Issue

U.S. active-duty military personnel and reservists have participated in a growing number of domestic terrorist plots and attacks, according to new data from CSIS. The percentage of all domestic terrorist incidents linked to active-duty and reserve personnel rose in 2020 to 6.4 percent, up from 1.5 percent in 2019 and none in 2018. Similarly, a growing number of current and former law enforcement officers have been involved in domestic terrorism in recent years. But domestic terrorism is a double-edged sword. In 2020, extremists from all sides of the ideological spectrum increasingly targeted the military, law enforcement, and other government actors—putting U.S. security agencies in the crosshairs of domestic terrorists.

Introduction

There is growing concern about the extent to which U.S. military and law enforcement personnel have perpetrated—and been victims of—domestic terrorism.¹ In March 2021, the U.S. Department of Defense (DoD) sent a report to the House and Senate Armed Services Committees which concluded: “DoD is facing a threat from domestic extremists (DE), particularly those who espouse white supremacy or white nationalist ideologies.” It continued that some domestic extremist networks “(a) actively attempt to recruit military personnel into their group or cause, (b) encourage their members to join the military, or (c) join, themselves, for the purpose of acquiring combat and tactical experience.”² In 2020, the FBI alerted the DoD that it had opened 143 criminal investigations involving current or former service members—of which nearly half (68) were related to domestic extremism. Most investigations apparently involved veterans, some of whom had unfavorable discharge records.³ The January 6, 2021, events at the U.S. Capitol raised additional concerns, since one reservist, one National Guard member, and at least 31 veterans were charged with conspiracy or other crimes.⁴ In addition, at least four police officers and three former officers faced federal charges for their involvement in storming the Capitol.⁵

In response to these developments, Secretary of Defense Lloyd Austin III pledged to intensify the DoD’s effort to combat extremism in the military, remarking, “It concerns me to think that anyone wearing the uniform of a soldier, or a sailor, an airman, Marine, or Guardian or Coast Guardsman would espouse these [extremist] sorts of beliefs, let alone act on them. But they do. Some of them still do.”⁶ Secretary Austin also signed a memo directing commanding officers and supervisors to conduct a one-day “stand-down” to discuss extremism in the ranks with their personnel.⁷ In addition, the DoD launched an investigation in January 2021 to determine the extent to which the department and military have implemented policies and procedures that prohibit advocacy and participation related to white supremacist, extremist, and criminal gang activity by active-duty personnel.⁸

Numerous police agencies also conducted investigations into extremism within their departments. As Mayor Bill de Blasio of New York City remarked, “Anyone who expresses racist views shouldn’t be a police officer, anyone who expresses white supremacist views shouldn’t be a police officer, anyone who encourages violence against our democratic institutions shouldn’t be a police officer.”⁹

While these steps are an important start, there has been little publicly available data about military or law enforcement involvement in domestic terrorism—as well as attacks against troops and police. In addition, some research is plagued by selection bias because it focuses on a single incident, such as the January 6 event at the U.S. Capitol.¹⁰ Without more systematic data, it is hard to gauge the severity of the problem and to make useful recommendations. To help fill the gap, this analysis utilizes CSIS’s data set of domestic terrorist plots and attacks since January 1, 1994, which was updated through the end of January 2021.

The data indicate that U.S. military personnel have been involved in a growing number of domestic terrorist plots and attacks. The percentage of attacks and plots committed by active-duty and reserve personnel rose in 2020 to 6.4 percent of all attacks and plots (7 of 110 total), up from 1.5 percent in 2019 (1 of 65 total) and none in 2018. Active-duty personnel perpetrated 4.5 percent of the attacks in 2020 (five incidents), and reservists conducted 1.8 percent (two incidents). While these individuals represent a tiny percentage of all current active-duty and reserve personnel, the increased number of incidents is still concerning.¹¹ The data also indicate a rise in law enforcement involvement in attacks. The growth is notable since individuals with a military or law enforcement background have skills that extremists want—such as proficiency in firing weapons, building explosive devices, conducting surveillance and reconnaissance, training personnel, practicing operational security, and performing other types of activities. The data should serve as a cautionary tale. While the numbers are relatively low, they are growing—and the military and law enforcement agencies need to take preventive action now.

There are several other notable findings from the data set. First, domestic extremists increasingly targeted the military, police, and other government agencies—putting security agencies in the crosshairs of domestic extremists. In 2020, government, military, and especially police personnel and facilities were the target of 38 percent of attacks, the most of any category. Second, there was a rise in the number of terrorist plots and attacks in 2020, despite a relatively low number of fatalities. This trend indicates that terrorism is a growing problem in the United States; there were more terrorist plots and attacks in 2020 than in any year since the CSIS data set started in 1994. Third, the motivations for terrorism have shifted dramatically over the past two decades, from religious extremists inspired by al-Qaeda and the Islamic State after September 11, 2001, to white supremacists, anarchists, and others today. White supremacists, extremist militia supporters, and other like-minded individuals were involved in two-thirds of the attacks and plots in 2020. Anarchists, anti-fascists, and other like-minded individuals perpetrated roughly 23 percent of the plots and attacks in 2020, a notable increase from recent years. And Salafi-jihadists were involved in a mere 5 percent—their lowest share of incidents since 2008.

The rest of this brief is divided into four sections. The first provides an overview of terrorism and outlines the data set. The second section assesses the main findings on military personnel and law enforcement, both as perpetrators and targets. The third outlines other findings from the CSIS data set. The fourth section offers brief implications.

Domestic extremists increasingly targeted the military, police, and other government agencies—putting security agencies in the crosshairs of domestic extremists.

Terrorism

This brief focuses on terrorism, which involves the deliberate use—or threat—of violence by non-state actors in order to achieve political goals and create a broad psychological impact.¹² Violence and the threat of violence are important components of terrorism. As Professor Bruce Hoffman of Georgetown University argues, terrorism is “the deliberate creation and exploitation of fear through violence or the threat of violence in the pursuit of political change.”¹³ U.S. Code, which is the official compilation of general and permanent laws of the United States, defines domestic terrorism under 18 U.S. Code § 2331 as “violent acts or acts dangerous to human life” that occur primarily within U.S. territory. It organizes terrorism acts into three components: the act is intended to “intimidate or coerce a civilian population,” it aims to “influence the policy of a government by intimidation or coercion,” and it involves “mass destruction, assassination, or kidnapping.”¹⁴

In focusing on terrorism, this brief does not cover the broader categories of hate speech or hate crimes. There is some overlap between terrorism and hate crimes, since some hate crimes include the use or threat of violence.¹⁵ But hate crimes can also include non-violent incidents, such as graffiti and verbal abuse. Hate crimes and hate speech are obviously concerning and a threat to society, but this analysis concentrates only on terrorism and the use—or threat—of violence to achieve political objectives. In addition, this analysis does not focus on protests, riots, looting, and broader civil disturbances—unless they meet the definition of terrorism. While these incidents are important to analyze, most are not terrorism. Some are not violent, while others lack a political motivation or the intention to create a broad psychological impact.¹⁶

Finally, while there is often a desire among government officials and academics to focus on terrorist groups and organizations, the terrorism landscape in the United States remains highly decentralized. Many are inspired by the concept of “leaderless resistance,” which rejects a centralized, hierarchical organization in favor of decentralized networks or individual activity.¹⁷ The decentralized nature of terrorism is particularly noteworthy regarding the use of violence, which CSIS data suggest is often planned and orchestrated by a single individual or small network.¹⁸

Based on this definition, the data set includes 980 cases of terrorist plots and attacks in the United States between January 1, 1994, and January 31, 2021. The data set includes such categories as the incident date, perpetrator, location, motivation, number of individuals wounded or killed, target, weapons used, and perpetrators’ current or former affiliations with law enforcement and the military. The data set—including the codebook, definitions, and limitations—is explained in more detail in a methodology supplement linked at the end of this analysis.

Military and Law Enforcement: Perpetrators and Targets

This section begins with a historical overview of military and law enforcement personnel involved in terrorism. It then examines more recent data about military and law enforcement personnel as both perpetrators and targets of terrorism. To be clear, this analysis does not focus on the broader question of extremism in the military, including its pervasiveness and causes. Nor does it offer a systematic analysis of why these numbers have increased, though it does offer some hypotheses. While these are important issues, the data set focuses on terrorist incidents.

In addition, there are important distinctions between the types of military personnel. While active-duty members serve full time in the military, reservists serve only part time and cannot be charged under the Uniform Code of Military Justice (UCMJ) when they are off duty. The military has less authority to respond to veterans who become involved in extremist behavior, but if their conduct violates the UCMJ, the military may be able to respond with retroactive demotions and reduced pensions.¹⁹

Historical Trends: A small number of military and law enforcement personnel have been involved in domestic extremism over the years. In her study of the white power movement, for example, Professor Kathleen Belew of the University of Chicago argues that the Vietnam War and other political, economic, and social factors led to a consolidation and expansion of white power activists, who attempted to recruit active-duty soldiers, reservists, and veterans involved in the Vietnam War.²⁰ In 1970 alone, the U.S. Marine Corps recorded over 1,000 incidents of racial violence at installations in the United States and Vietnam, including violent altercations between black and white Marines at Camp Lejeune, North Carolina.²¹ While most of these were not acts of terrorism, they still contributed to an enabling environment for extremist acts.

In addition, several influential extremists in the 1970s, 1980s, and 1990s served in the U.S. military or law enforcement agencies. One of the most prominent white supremacist figures was Louis Beam, who enlisted in the Army when he was 19 years old and fought in the Vietnam War.²² In his speeches and writings—including his influential Essays of a Klansman—Beam argued that activists needed to continue waging the war on U.S. territory using guerrilla warfare.²³ Beam was not alone. Randy Duey, a member of the white supremacist group The Order, was an Air Force veteran and instructor at the survival school at Fairchild Air Force Base in Spokane, Washington.²⁴ Randy Weaver—a Christian Identity adherent who held white supremacist and anti-government views, and who was involved in the 1992 Ruby Ridge standoff near Naples, Idaho—was a former U.S. Army engineer.²⁵ Timothy McVeigh, who carried out the 1995 Oklahoma City bombing that killed 168 people and injured more than 680 others, enlisted in the U.S. Army in 1988 and fought in Iraq during Operation Desert Storm. There were also other veterans involved in extremism, such as William Potter Gale, Richard Butler, Bo Gritz, Frazier Glenn Miller, and Eric Rudolph.²⁶

In addition, some former law enforcement officers were involved in domestic terrorism, including those that were members or sympathizers of the Ku Klux Klan.²⁷ Among the most prominent was Gerald “Jack” McLamb, a retired Phoenix police officer who urged resistance to those who supported a one-world government and wrote a 75-page manifesto titled, Operation Vampire Killer 2000: American Police Action Plan for Stopping World Government Rule.²⁸ White supremacist groups also attempted to infiltrate and recruit from law enforcement agencies, according to FBI assessments.²⁹

Among the most prominent white power books during this period was The Turner Diaries, a dystopian novel that drew heavily on the concept of military and law enforcement personnel as white power soldiers. Written by William Pierce and published under the pseudonym Andrew Macdonald, The Turner Diaries depicts a violent revolution in the United States which leads to the overthrow of the federal government, a nuclear war, and a race war that results in the extermination of non-whites. In a reference to the U.S. military’s experience fighting communist governments and insurgent groups across the globe, the protagonist, Earl Turner, notes, “We have had the example of decades of guerrilla warfare in Africa, Asia, and Latin American to instruct us.”³⁰ William Pierce and his National Alliance, a white supremacist and neo-Nazi political organization, attempted to recruit military and law enforcement personnel.³¹

According to FBI data, 37 percent of lone offender terrorists in the United States between 1972 and 2015 served in the military.³² But in the decade after September 11, 2001, there were few attacks by active-duty, reservist, or law enforcement personnel, though extremist groups attempted to infiltrate the military and law enforcement.³³ In June 2006, for example, Shayne Allyn Ziska, a state correctional officer in California, was sentenced to 17.5 years in prison for aiding a white supremacist prison gang called the Nazi Low Riders.³⁴ But the trends began to change over the past several years.

Military: As Figure 1 shows, there was an increase in the percentage of domestic terrorist plots and attacks perpetrated by active-duty and reserve personnel in recent years.³⁵ In 2020, 6.4 percent of all domestic terrorist attacks and plots (7 of 110 total) were committed by one or more active-duty or reserve members—an increase from 1.5 percent in 2019 (1 of 65 total) and none in 2018. While the attacks in 2021 account for only one month, the numbers in January 2021 showed another increase: 17.6 percent of domestic terrorism plots and attacks (3 of 17 total) were committed by active-duty or reserve personnel.

On January 19, 2021, for example, the FBI and U.S. Army Counterintelligence Coordinating Authority arrested a U.S. Army soldier, Cole James Bridges, at Fort Stewart after he conspired to blow up the 9/11 Memorial in New York and attempted to provide support to the Islamic State.³⁶ On May 30, 2020, authorities in Las Vegas, Nevada, arrested Andrew Lynam, an Army reservist, alongside Navy veteran Stephen T. Parshall and Air Force veteran William L. Loomis—all self-identified Boogaloo Bois—for conspiring to firebomb a U.S. Forest Service building and a power substation to sow chaos during the protests held in response to the murder of George Floyd.³⁷ On June 10, 2020, the FBI arrested Army Private Ethan Melzer, who sent sensitive U.S. military information to the Order of the Nine Angles (O9A), an occult-based neo-Nazi and white supremacist group, in an attempt to facilitate a mass-casualty attack on Melzer’s Army unit.³⁸ On May 29, 2020, Air Force Staff Sergeant Steven Carrillo, a supporter of the Boogaloo Bois who wanted to ignite a civil war, shot and killed Pat Underwood, a protective security officer, and wounded his partner in Oakland, California. Carrillo also killed a Santa Cruz County sheriff’s deputy in Ben Lomond, California, with an assault rifle on June 6, 2020.³⁹

In addition, the January 6, 2021, attack at the U.S. Capitol included veterans, reservists, a member of the National Guard, members of several militias and extremist organizations (such as the Sons of Liberty New Jersey, Groyper Army, Oath Keepers, Proud Boys, Boogaloo Bois, and Three Percenters), supporters of the extremist conspiracy QAnon, and other groups and networks. No participants have been identified as active-duty military personnel. On January 13, the FBI arrested Jacob Fracker, a U.S. Army National Guardsman, for his involvement in the Capitol attack.⁴⁰ As Fracker explained in an Instagram post, “Sorry I hate freedom? Sorry I fought for it and lost friends for it? . . . I can protest for what I believe in and still support your protest for what you believe in. Just saying . . . after all, I fought for your right to do it.”⁴¹

Veterans have also been involved in domestic terrorist attacks and plots.⁴² In October 2020, for example, the FBI arrested Adam Fox, Barry Croft, and several other accomplices in a plot to kidnap and potentially execute Michigan Governor Gretchen Whitmer. Members of this network, which had ties to militias in Michigan and other states, referred to Governor Whitmer as a “tyrant” and claimed that she had “uncontrolled power right now.”⁴³ Paul Edward Bellar, a U.S. Army veteran who had been honorably discharged roughly a year before his arrest, trained the group on the use of firearms, medical care, and other tactical skills.⁴⁴ Veterans consistently committed more attacks and plots than active-duty and reserve troops—including 10 percent of all domestic terrorist attacks and plots since 2015, according to CSIS data.

Domestic extremist groups and networks have also attempted to recruit veterans, active-duty personnel, and reservists. To be clear, this analysis is not suggesting that individuals serving in the military or who are veterans are more inclined to embrace extremism than the general population or are attracted to extremist ideologies. Nevertheless, violent far-right and far-left networks have solicited military personnel because of their skill sets. According to one estimate, veterans and active-duty members of the military currently make up roughly 25 percent of active militia members.⁴⁵ Such organizations as the Proud Boys, Oath Keepers, and Three Percenters include active-duty personnel, reservists, veterans, and law enforcement personnel.⁴⁶ The Boogaloo Bois, anti-fascists, and extremists with other motivations have also included active-duty personnel, reservists, and veterans.

Law Enforcement: CSIS data identified six incidents since 1994 in which current or former law enforcement personnel committed domestic terrorist plots and attacks—though all six cases occurred since 2017. As with active-duty and reserve military personnel, this is an increase, despite representing a small fraction of all law enforcement professionals in the United States. Between October 2020 and January 2021, three domestic terrorist attacks or plots involved current law enforcement officers. For example, Joseph Wayne Fischer, an off-duty patrolman from Pennsylvania, participated in the January 6, 2021, Capitol attack and was reportedly in the front wave of rioters pushing back police officers. Fischer was charged with multiple criminal offenses, including obstruction of law enforcement and violent entry.⁴⁷ At least four current police officers and three former officers were allegedly involved in the January 6 incident at the Capitol.⁴⁸

Former law enforcement officers were involved in two incidents in 2017 and one in 2020. On October 19, 2020, former Houston police captain Mark Anthony Aguirre ran a repairman off the road, pinned him to the ground, and threatened him at gunpoint, claiming that the man was transporting 750,000 false ballots as part of an election fraud scheme—a conspiracy theory pushed by the group Liberty Center for God and Country.⁴⁹

Terrorist Targeting of Military and Law Enforcement: CSIS data also show that the U.S. government, military, and law enforcement were increasingly targeted by domestic terrorists. As shown in Figure 2, government, military, and police personnel and facilities were the targets of 34 of 89 attacks in 2020 from perpetrators of varying ideologies, making them the most frequent targets.⁵⁰ Of these 34 attacks, 19 targeted the government, 15 targeted law enforcement, and 1 targeted the military.⁵¹ The attacks were led by perpetrators of various ideologies, including violent far-right, violent far-left, religious, and the Boogaloo Bois—who were responsible for all attacks coded as “other” in the 2020 data.

In addition, the percentage of domestic terrorist attacks against government, military, and police agencies increased over the past five years. In 2020, 38 percent of all domestic terrorist attacks targeted these institutions. This was the second-highest percentage since at least 1994—exceeded only in 2013, when attacks against government, military, and police targets comprised 46 percent of all attacks. The frequency of attacks against military and—in particular—law enforcement targets may be due, in part, to a growing belief by extremists that security agencies are the most visible arm of an illegitimate and oppressive government.

For some anti-fascists, the police are quintessential symbols of a repressive state—including against minority populations.⁵² “As for the police . . . the historical record shows that along with the military they have also been among the most eager for a ‘return to order,’” wrote Mark Bray in Antifa: The Anti-fascist Handbook.⁵³ This explains why some anti-fascists and anarchists conducted attacks against police stations and police vehicles during the protests in the summer of 2020. As highlighted by the events on January 6, 2021, however, some on the violent far-right also consider law enforcement the main security arm of a government they believe is illegitimate. “Traitors! Traitors! Traitors!” chanted some individuals on the Capitol steps on January 6. “The blue does not back you,” read a message from a pro-Proud Boys group on the social networking service Parler, “They back the men who pay them.”⁵⁴

While this analysis does not conduct a comprehensive analysis of why there was a rise in the number and percentage of active-duty and reserve personnel involved in domestic terrorist attacks and plots, there are several hypotheses worth considering. For example, it would be worth examining whether the deployment of soldiers to controversial battlefields such as Iraq and Afghanistan triggered a backlash against U.S. society and the government (much like with the Vietnam War); whether military personnel have been increasingly influenced by the political polarization prevalent in the United States; or whether military personnel have been more active on the internet and social media platforms, which has contributed to radicalization. In addition, there may be other social, economic, educational, or cultural variables at play, along with the possible proliferation of charismatic individuals that have spread propaganda in the military.

Other Findings

CSIS also examined trends in the number and characteristics of attacks and plots. This section analyzes the data in two parts: number of incidents and fatalities, and perpetrator ideology.

Incidents and Fatalities: In 2020, the number of domestic terrorist attacks and plots increased to its highest level since at least 1994, though fatalities were relatively low. Across all perpetrator ideologies, there were 110 domestic terrorist attacks and plots in 2020—an increase of 45 incidents since 2019 and 40 more incidents than in 2017, the year which previously had the most terrorist attacks and plots since the beginning of the data set. Despite this sharp increase in terrorist activity, the number of fatalities from domestic terrorist attacks was at its lowest level since 2013. Five people were killed in terrorist attacks in 2020—an 86 percent decrease from 2019, when 35 individuals died in terrorist attacks.

There are several possible explanations for this drop in lethality. First, there were 21 terrorist plots recorded in 2020 which were disrupted before an attack could take place. Some decrease in fatalities, then, may be attributed to the effective work of the FBI and other law enforcement agencies in preventing attacks.

Second, there were no mass-casualty terrorist attacks in 2020. All five victims were killed with firearms in five separate attacks. In comparison, there were seven fatal attacks each in 2018 and 2019, resulting in 19 and 35 fatalities, respectively. Though the number of fatal attacks was similar, each of these previous years included a mass-casualty attack that significantly raised the total. In 2018, Robert Bowers murdered 11 people at the Tree of Life synagogue in Pittsburgh, Pennsylvania, and in 2019, Patrick Crusius murdered 22 people at a Walmart in El Paso, Texas. This alone does not explain the reduction, however, because there was ample opportunity for similar mass-casualty events in 2020. As highlighted in Figure 2, soft targets such as demonstrators and private individuals were frequent targets of terrorist attacks and plots. Furthermore, previous CSIS analysis found that vehicles were increasingly common weapons in terrorist attacks in 2020, joining firearms, explosives, and incendiaries as some of the most commonly used weapons—all of which have high potential lethality.⁵⁵

Third, the restraint shown in those attacks may point to perpetrators prioritizing sending a message through fear rather than fatalities. Though there has been substantial rhetoric about bringing about a second civil war—such as from the Boogaloo Bois and some white supremacists—many extremists may wait for their ideological adversaries to act first, whether through violent action or policy change that is perceived as an existential threat. This is consistent with the philosophy put forward by militia leaders such as the Three Percenters’ co-founder Mike Vanderboegh, who in 2008 advised his followers not to “fire first” and instead to wait and act under the justification of the common defense so as to “not cede the moral high ground.”⁵⁶

Perpetrator Ideology: CSIS also coded the ideology of perpetrators into one of five categories: ethnonationalist, religious, violent far-left, violent far-right, and other. (The link to the methodology, which includes definitions of these categories, can be found at the end of this brief.) All religious attacks and plots in the CSIS data set were committed by terrorists motivated by a Salafi-jihadist ideology.

White supremacists, extremist militia members, and other violent far-right extremists were responsible for 66 percent of domestic terrorist attacks and plots in 2020—roughly consistent with their share in other recent years.⁵⁷ For example, on June 7, Harry H. Rogers—a self-proclaimed leader of the Ku Klux Klan—intentionally drove his pick-up truck into a crowd of Black Lives Matter demonstrators in Henrico, Virginia. One protester was injured, and Rogers received a six-year prison sentence.⁵⁸ In addition, anarchists, anti-fascists, violent environmentalists, and other violent far-left extremists conducted 23 percent of terrorist attacks and plots in 2020—an increase from the previous three years, in which violent far-left incidents comprised between 5 and 11 percent of all domestic terrorist attacks and plots. For example, on August 29 in Portland, Oregon, Michael Reinoehl—an Antifa extremist—followed two members of the far-right group Patriot Prayer and then shot and killed one of them, Aaron “Jay” Danielson.⁵⁹

Meanwhile, the portion of attacks and plots inspired by a Salafi-jihadist ideology fell to 5 percent in 2020—a sharp decline compared to recent years such as 2019, in which they comprised 29 percent of incidents. For example, on May 21, Adam Aalim Alsahli—a Syrian-born U.S. citizen inspired by jihadist figures such as Ibrahim al-Rabaysh—drove his vehicle into the gate of Naval Air Station Corpus Christi in Texas and then opened fire on a guard.⁶⁰ The proportion of attacks and plots by ideology in January 2021 remained roughly consistent with the 2020 data.

Policy Implications

U.S. military and law enforcement agencies need to better understand the scope of the problem through better data collection and analysis. The U.S. military has already taken steps along these lines in such areas as sexual assault and suicides. At the moment, the number of active-duty military personnel, reservists, and police involved in domestic terrorism is relatively small, though it is rising.⁶¹

These challenges will persist since extremist networks seek to embed their members in the military and law enforcement agencies and to actively recruit current and retired personnel.⁶² The Russian government has also recognized that these groups may be vulnerable to extremist ideologies and has targeted active-duty personnel, reservists, veterans, and police through an aggressive cyber and disinformation campaign on digital platforms.⁶³ Military and law enforcement personnel have valuable skills that extremist networks want, such as small unit tactics, communications, logistics, reconnaissance, and surveillance. They may also have access to weapons and explosives. In January 2021, for example, several pounds of C-4 explosives went missing from a Marine Corps base in Twentynine Palms, California.⁶⁴

Any effort to disrupt extremism in the military must address all stages of service. In vetting new recruits and renewing existing security clearances, for example, revisions to the SF-86 process should help identify individuals associated with extremist networks. At least one reservist who participated in the January 6 Capitol attack held a security clearance and was well known among his colleagues for harboring extremist views.⁶⁵ An FBI database of lone offender terrorism in the United States indicated that 10 percent of offenders between 1972 and 2015 took steps to join the military but were either disqualified during the application process or dropped out after realizing they might not meet the qualifications.⁶⁶ Deterrence is critical. The DoD should publicly announce any changes to its vetting processes to deter those with extremist views from even attempting to join the military.

U.S. military and law enforcement agencies need to better understand the scope of the problem through better data collection and analysis.

The military and police should also increase their focus on counterextremism education as well as offer clear reporting and oversight processes for current service members and police officers. This may include training personnel on identity signaling within extremist networks, including symbols displayed in tattoos and on apparel. On the law enforcement side, organizations such as the International Association of Chiefs of Police (IACP) and the Police Executive Research Forum (PERF) should increase efforts to better understand and counter extremism within police forces. Finally, there should be a focus on veterans and individuals exiting the services, who are at an increased risk of recruitment.⁶⁷

A data-driven understanding of the nature of extremist behavior among military and law enforcement personnel could help inform and prioritize these efforts. For example, CSIS analysis found that while there was an increase in active-duty and reserve personnel involvement in terrorist attacks and plots, the majority of perpetrators affiliated with the military in recent years were veterans. Though the military does not have as much influence over the behavior of veterans once they separate from the military, the DoD could pull service records for all military-affiliated perpetrators and gather information to better understand the causes. Such patterns could inform efforts to disrupt radicalization pathways before individuals leave the military. Congressionally directed or agency-initiated efforts by the Department of Veterans Affairs (VA) could also help identify and counter extremist activity among veterans, and data-sharing agreements between the DoD and VA could strengthen deradicalization efforts.

Simultaneously, the U.S. government should prepare for the military, law enforcement, and other government agencies to continue to be frequent targets of domestic terrorism. Attacks against these institutions are increasing from extremists of diverse ideologies. This risk may be exacerbated by such issues as gun control, immigration, and Covid-19 policies. The DoD and law enforcement agencies should conceptualize efforts to counter domestic extremism as an issue of self-defense and support for their personnel. This concern may shape strategies to eliminate extremist ideology among service members. For example, individual commanders could work to build a trusting environment to report and address these problems framed in terms of unit defense and cohesion, rather than levying blame.

Furthermore, concerns about extremism in the military and law enforcement are not confined to the United States.⁶⁸ Germany has faced significant problems, from which the United States may be able to draw some lessons. In November 2020, a German government investigation identified 26 soldiers and 9 police officers who organized and participated in online chat groups that shared far-right, anti-Semitic, and neo-Nazi content.⁶⁹ The investigations came on the heels of an October 2020 report by the Federal Office for the Protection of the Constitution (Bundesamt für Verfassungsschutz, or BfV), which documented more than 1,400 cases of far-right extremism in the police and intelligence services over the previous four years.⁷⁰ In 2020, Germany’s Defense Ministry identified 20 far-right extremists within a company of the country’s elite special forces, the Kommando Spezialkräfte. The German military disbanded the 2nd Company, though 48,000 rounds of ammunition and more than 135 pounds of explosives went missing from the unit’s stockpiles.⁷¹ More broadly, the European police agency Europol warned in a confidential report that extremist groups in Europe attempted to bolster their “combat skills” by recruiting military and police members.⁷²

Of broader concern, the U.S. government does not publicly release data on terrorist attacks and plots, nor on the characteristics of perpetrators. However, if a centralized data collection effort were established, data analysis could offer an objective mechanism for apportioning counterterrorism resources and efforts relative to actual threats. For example, CSIS data show that domestic terrorist attacks and plots from violent far-right and far-left actors are on the rise, while Salafi-jihadist-inspired terrorism is declining. This presents a clear case for continuing to redirect resources away from Salafi-jihadist to other types of extremism.

Despite these challenges, one reason for hope is the low number of deaths from domestic terrorism. Terrorism from violent far-right and far-left extremists has not killed many Americans—at least not recently. This could change, of course, as Timothy McVeigh illustrated in 1995. Terrorism expert Brian Jenkins once wrote that “terrorism is theater” and “terrorists want a lot of people watching, not a lot of people dead.”⁷³ These aphorisms may not have been true of al-Qaeda and Islamic State adherents, as Jenkins recognized.⁷⁴ But the data certainly raise questions about how far most domestic terrorists are willing to go today.

Seth G. Jones is senior vice president and director of the International Security Program at the Center for Strategic and International Studies (CSIS) in Washington, D.C, and author most recently of Three Dangerous Men: Russia, China, Iran, and the Rise of Irregular Warfare (W.W. Norton). Catrina Doxsee is a program manager and research associate with the Transnational Threats Project at CSIS. Grace Hwang is a research assistant with the Burke Chair in Strategy and Transnational Threats Project at CSIS. Jared Thompson is a research assistant with the Transnational Threats Project at CSIS.

The authors give special thanks to Bruce Hoffman, Cynthia Miller-Idriss, Colin Clarke, and David Brannan for their review of the document—including the data set—and their helpful critiques. Thanks also to Jerry Bennett, Mark Cancian, James Cheney, Eric McQueen, Joseph Moye, and Jacob Ware for their comments. Finally, thanks to Nicholas Harrington for his help in updating the data set.

For an overview of the methodology used in compiling the data set, please see here.

This brief is made possible by general support to CSIS. No direct sponsorship contributed to this brief.

CSIS Briefs are produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s). 

© 2021 by the Center for Strategic and International Studies. All rights reserved.

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