What is the Threat to the United States?

The jihadist terrorist threat to the United States is relatively limited. The threat posed by ISIS is receding, and the number of terrorism-related cases in the United States has declined substantially since its peak in 2015, though the nature and level of the threat is unlikely to change in a fundamental manner.

The most likely threat to the United States comes from terrorists inspired by ISIS or in contact with its virtual recruitment networks, as opposed to ISIS-directed attacks of the sort seen in Paris in 2015 and Brussels in 2016. The most typical threat to the United States remains homegrown rather than from infiltrating foreign nationals. The travel ban is thus not an effective response to this threat. Finally, the United States faces a continued threat from non-jihadist terrorists, most notably those motivated by far-right ideologies.

The threat to the United States from jihadist terrorism remains relatively limited. New America’s “Terrorism in America After 9/11” project tracks the 449 cases of individuals who have been “charged” with jihadist terrorism-related activity in the United States since September 11, 2001.¹

In the 17 years since the 9/11 attacks, individuals motivated by jihadist ideology have killed 104 people inside the United States. Every one of those deaths is a tragedy, but they are not national catastrophes as 9/11 was. The death toll from jihadist terrorism over the past 17 years is far lower than what even the most optimistic of analysts projected in the immediate aftermath of the 9/11 attacks. Al-Qaeda and its breakaway faction, ISIS, have failed to direct a successful attack in the United States since the 9/11 attacks. Indeed, no foreign terrorist organization has carried out a successful attack in the United States since 9/11, and none of the perpetrators of the 13 lethal jihadist attacks in the United States since 9/11 received training from a foreign terrorist group.

The rise of ISIS caused many to fear that the threat had fundamentally changed. Yet four years after the declaration of the caliphate, ISIS has not managed to direct an attack inside the United States, and its territorial losses make it increasingly unlikely that it will do so in the future.

ISIS did manage to inspire an unprecedented number of Americans to conduct attacks and otherwise engage in jihadist activity. In 2015, 80 people were charged with jihadist terrorism activity, the highest number in the post-9/11 era. More than three-quarters of all deaths caused by jihadists in the United States since the 9/11 attacks occurred in 2014 or later, the period when ISIS came to prominence, despite those years accounting for less than a third of the post-9/11 era. More than half of the deadly attacks since 9/11 were ISIS-inspired in some way.

The threat posed by ISIS is receding, and the number of terrorism-related cases in the United States has declined substantially.

However, ISIS’ ability to inspire such activity is declining with the demise of its territorial holdings in Iraq and Syria and the resultant stanching of the “foreign fighter” flow to the region. The number of cases of individuals being charged with terrorism-related crimes has decreased since the peak of 80 cases in 2015. There has been a particularly low number of charges brought this year, with only eight new cases as of the end of August.

Policymakers and analysts should not expect the threat to the United States to fundamentally change as a result of the collapse of ISIS’ holdings in Iraq and Syria. Because the ISIS threat to the United States was homegrown, inspired and relatively limited even at the peak of ISIS’ strength, rather than being directed from Syria, the impact of ISIS’ territorial collapse on the threat is limited.² While the number of cases has declined since 2015, ISIS-inspired attacks have continued, as demonstrated by Sayfullo Saipov’s truck ramming attack that killed eight people in Manhattan in October 2017, the same month that ISIS lost control of its capital in Raqqa.

In addition, policymakers should be wary of reading too much into the number of prosecutions. There may be cases that are not yet public but were charged in 2018, and the number of prosecutions can reflect prosecutorial decisions regarding how aggressive to be. That said, the low number of cases is notable.

The limited threat to the United States is in large part the result of the enormous investment the country has made in strengthening its defenses against terrorism in the post-9/11 era. According to a study group created by the Stimson Center, one of whose members was Luke Hartig, a New America International Security program fellow and former senior director for counterterrorism at the National Security Council, the United States spent $2.8 trillion on counterterrorism efforts from 2002 to 2017, constituting almost 15 percent of discretionary spending during that time frame.³

That effort has made the United States a hard target.⁴ On 9/11, there were 16 people on the U.S. “No Fly” list.⁵ In 2016, there were 81,000 people on the list.⁶ In 2001, there were 35 Joint Terrorism Task Force “fusion centers,” where multiple law enforcement agencies worked together to chase down leads and build terrorism cases.⁷ Seventeen years later, there are more than 100.⁸ Before 9/11, there was no Department of Homeland Security, National Counterterrorism Center or Transportation Security Administration.

In addition, today the public is far more aware of the threat posed by jihadist terrorists. In December 2001, it was passengers on board an American Airlines jet that disabled the “shoe bomber,” Richard Reid.⁹ Eight years later, it was again passengers who tackled the “underwear bomber,” Umar Farouk Abdulmutallab, on Northwest Flight 253 as it flew over Detroit. The following year, it was a street vendor who spotted a suspicious SUV parked in Times Square that contained a bomb planted there by Pakistani Taliban recruit Faisal Shahzad.¹⁰ Suspicious members of the public have provided tips that led to the initiation of investigations in 7 percent of the 407 terrorism cases since 9/11 that were prevented or detected before the perpetrator could carry out a plot.

Policymakers and analysts should not expect the threat to the United States to fundamentally change as a result of the collapse of ISIS’ holdings in Iraq and Syria.

In addition to the general public’s awareness, family members of accused terrorists and members of their local communities have also stepped up to report suspicious activity. In 14 percent of jihadist terrorism cases since 9/11 that were prevented or detected prior to an attack, community or family members provided a tip that initiated the investigation — the second most important method of detecting terrorism suspects, surpassed only by informants, who initiated 22 percent of cases.

Among those detected thanks to tips from community and family members was Moner Abu Salha, a Floridian who traveled and fought with the Nusra Front in Syria before returning to the United States undetected. When he tried to recruit friends to join him in Syria, where he eventually died conducting a suicide attack against Syrian troops in 2014, one of his friends reported him to the FBI.¹¹ Similarly, it was a 911 call from the parents of North Carolinian Justin Sullivan in June 2015 that put him on the government’s radar.¹² Had it not been for that tip, Sullivan, who had already committed a murder and who was in contact with Junaid Hussain, an ISIS virtual recruiter, might have succeeded in his plot to conduct a lethal attack.¹³

Adding to these defenses and law enforcement techniques are the U.S. campaigns overseas. In 2017, the United States allocated more than $73 billion to intelligence activities.¹⁴ Before 9/11, the budget was about one third of that — $27 billion.¹⁵ The U.S. drone wars in Pakistan, Yemen and elsewhere have decimated the leadership of jihadist groups.¹⁶ In June 2018, an American drone strike in Afghanistan killed Mullah Fazlullah, the leader of the Pakistani Taliban.¹⁷ In April 2018, the United States killed the ISIS Afghanistan branch’s leader for northern Afghanistan.¹⁸ In July 2017, the United States killed Abu Sayed, the leader of ISIS’ branch in Afghanistan; he was the third leader of the affiliate killed in an American strike in a year.¹⁹ In May 2016, the United States killed the leader of the Taliban, Mullah Akhtar Mohammad Mansour, in a drone strike in Pakistan.²⁰ In 2015, a U.S. drone strike killed Nasir al-Wuhayshi, then al-Qaeda’s second in command and the leader of Al-Qaeda in the Arabian Peninsula.²¹

By the start of the Trump administration, the threat inside the United States was overwhelmingly lone-actor, ISIS-inspired attacks such as the one in Orlando in June 2016. This threat has stressed law enforcement, given the diversity of the perpetrators and the lack of organization needed to conduct such attacks. However, it is a far cry from the type of attack that al-Qaeda carried out on 9/11.

Law enforcement and intelligence services will of course still need to combat and monitor the threat to the homeland from foreign terrorist organizations. Plots such as the 2009 underwear bomb attempt; the 2009 case in which three Americans trained with al-Qaeda and returned with a plan to bomb the New York City subway; and the 2010 failed Times Square bombing by Faisal Shahzad, who trained with the Pakistani Taliban, are sufficient reminders of this fact.

Since 2014, the year ISIS burst onto the global scene after seizing Mosul and declaring the caliphate, there have been eight deadly jihadist attacks in the United States. Eighty-three people were killed, accounting for more than three-quarters of all deaths caused by jihadists in the United States since the 9/11 attacks. Seven of the eight were ISIS-inspired attacks, the exception being Muhammad Youssef Abdulazeez’s 2015 attacks at a recruiting station and a U.S. Navy Reserve center in Chattanooga, Tennessee, inspired by jihadist ideology in general.

• In March 2018, Corey Johnson, a 17-year-old white convert, stabbed three people during a sleepover in Palm Beach Gardens, Florida — a 13-year-old boy, another teenager and that teen’s mother — killing the 13-year-old.²² According to police, Johnson had converted to Islam, watched jihadist videos online and admitted to committing the stabbings due to his religious beliefs.
• In October 2017, Sayfullo Saipov, a 29-year-old Uzbek permanent resident of the United States, killed eight people when he drove a truck into the Hudson River Park’s bike path in New York City.²³ Saipov left a note saying he conducted the attack for ISIS.
• In January 2017, Joshua Cummings, a 37-year-old white convert to Islam from Texas, shot and killed a transit guard in Denver, Colorado. In the aftermath of the attack, Cummings pledged allegiance to ISIS.²⁴ ISIS did not claim Cummings’ attack.
• In June 2016, Omar Mateen killed 49 people in a shooting at the Pulse nightclub in Orlando, Florida. Mateen pledged allegiance to ISIS on social media the day of the attack.²⁵ Unlike the case of Cummings, ISIS eagerly claimed Mateen’s attack.
• In December 2015, Syed Rizwan Farook and Tashfeen Malik killed 14 people in an attack in San Bernardino, California. The attackers pledged allegiance to ISIS via Facebook.²⁶ ISIS claimed the attack, though the Arabic version of the claim described the attackers only as supporters of ISIS.²⁷ Shortly after the attack, then-FBI Director James Comey said the FBI had not found any evidence of contact between Farook and Malik and foreign terrorists.²⁸
• In July 2015, Mohammad Youssef Abdulazeez fatally shot five people at military facilities in Chattanooga, Tennessee. In December 2015, Comey stated, “There is no doubt that the Chattanooga killer was inspired, motivated by foreign terrorist organization propaganda,” but he also said it was difficult to determine which group specifically inspired him.²⁹ Abdulazeez did not pledge allegiance to ISIS, and ISIS did not claim the attack.
• In September 2014, Alton Nolen beheaded a coworker of his at the Vaughn Foods processing center in Moore, Oklahoma. Nolen had an ISIS flag in his car and his social media activity suggested he was influenced by jihadist ideology.³⁰ ISIS had no direct involvement in the attack.
• From April to June 2014, Ali Muhammad Brown fatally shot four people in a killing spree across Washington state and New Jersey, writing in his journal that he supported ISIS and telling police that he committed the killings in retaliation for American foreign policy.³¹ Brown did not receive operational direction from ISIS.

A number of these attackers had personal troubles. This should warn against explaining their acts simply as motivated by militant Islamist ideology:

• Corey Johnson had a long history of fascination with extremist violence of multiple stripes — not just jihadism — including white supremacy and dictators like Stalin and Hitler.³² He also had a history of behavioral issues and according to one report he stalked a fellow student while in middle school.³³
• Joshua Cummings had clashed with multiple people in his community. His local newspaper in Texas, the Pampa News, had stopped publishing his stories on martial arts — Cummings had taught martial arts classes at a studio in Pampa — in 2015 due to his obsessions and conspiracy theorizing.³⁴
• Omar Mateen had a long history of stalled career goals, disruptive behavior and domestic violence.³⁵
• Mohammad Abdulazeez suffered from depression.³⁶
• There are significant questions regarding Alton Nolen’s mental health. Though he was ruled competent to stand trial, Nolen’s defense presented evidence that he suffers from mental health issues, and the psychologist cited by the prosecution acknowledged he had symptoms of mental illness but argued there was not enough for a diagnosis.³⁷ In addition, Nolen’s attack was triggered by his suspension from work, albeit seemingly for a complaint regarding his racial politics.³⁸ He reportedly told police he was motivated by what he viewed as discrimination in the workplace.³⁹ Nolen also had a criminal history involving drug charges and assault and battery of a police officer, for which he served two years in prison.⁴⁰
• Ali Muhammad Brown was in the midst of what the judge in his case called a “downward spiral of criminality,” having previously been convicted of bank fraud, assault and communication with a minor for immoral purposes.⁴¹

There have been 12 nonlethal terrorist attacks in the United States since 2014 by individuals motivated by jihadist ideology, mostly by ISIS.

• On January 14, 2018, Tnuza Hassan, a 19-year-old U.S.-born citizen, set a series of fires at St. Catherine University in Minnesota, where she had been a student, as retaliation for U.S. foreign policy.⁴² No one was hurt in the incident, and she was later charged with attempting to provide material support to terrorists with relation to attempts to join jihadists abroad, arson and false statements.⁴³
• On December 11, 2017, Akayed Ullah, a 27-year-old legal permanent resident from Bangladesh, detonated a pipe bomb near New York’s Port Authority bus terminal, injuring five people.⁴⁴ Ullah pledged allegiance to ISIS, saying he conducted the attack for them.
• On November 12, 2017, Mahad Abdirahman, a 20-year-old naturalized citizen from Somalia who had been ruled to be suffering from schizophrenia and spent much of 2017 before his attack in a mental institution, stabbed and injured two people at the Mall of America in Bloomington, Minnesota.⁴⁵ Abdirahman said during court proceedings that he conducted the attack for ISIS.⁴⁶
• On June 21, 2017, Amor Ftouhi, a 49-year-old dual Canadian-Tunisian citizen, stabbed and injured a security guard at the airport in Flint, Michigan, yelling “Allahu Akbar!” and referencing U.S. actions in Syria.⁴⁷
• In November 2016, Abdul Razak Ali Artan, an 18-year-old permanent resident who had come to the United States as a refugee from Somalia after living in Pakistan, injured 11 people after ramming his vehicle into and proceeding to stab people with a knife at Ohio State University.⁴⁸ ISIS claimed the attack, and Artan had made a Facebook posting citing Anwar al-Awlaki prior to the attack.⁴⁹
• In September 2016, Dahir Adan, a 20-year-old Somali-American naturalized citizen, injured 10 people when he went on a stabbing rampage at a mall in Minnesota. ISIS claimed the attack, but investigators have found no direct link to the group.⁵⁰
• Also in September 2016, Ahmad Khan Rahami, a 28-year-old naturalized citizen whose journal mentioned both ISIS and al-Qaeda leaders, detonated bombs in Manhattan and at the Jersey Shore, injuring 31 people.⁵¹
• In August 2016, Wasil Farooqui, a 20-year-old U.S.-born citizen who according to police said he was hearing voices, attacked people with a knife in Roanoke, Virginia.⁵² Farooqui had reportedly attempted to travel to fight in Syria in the past.⁵³
• In January 2016, Edward Archer, a 30-year-old African-American man, shot and injured a police officer in Philadelphia. Archer claimed to be loyal to ISIS.⁵⁴
• In November 2015, Faisal Mohammad, 18, a student at the University of California, Merced and U.S.-born citizen, stabbed and injured four people on the campus.⁵⁵ According to the FBI, he had visited pro-ISIS websites, read its propaganda and had a printout of the ISIS flag in his backpack.⁵⁶
• In May 2015, two U.S.-born citizens, Elton Simpson, 30, and Nadir Soofi, 34, opened fire on an “art contest” in Garland, Texas, organized by the American Freedom Defense Initiative that involved drawing cartoons of the Prophet Muhammad. Simpson had exchanged tweets with Mujahid Miski and Junaid Hussain, two well-known ISIS virtual recruiters who were based in Somalia and Syria, respectively, in the run-up to the attack.⁵⁷ This was the only ISIS-enabled — as opposed to ISIS-inspired — attack in the United States injuring one person before the gunmen were killed by police.
• In October 2014, Zale Thompson, a 32-year-old U.S.-born citizen, attacked four police officers in Queens, New York, with a hatchet. According to New York City police, he was inspired by terrorist propaganda including that of ISIS.⁵⁸

As with the deadly attackers, some of the nonlethal attackers had prior personal issues, histories of violence or mixed ideological influences that raise questions as to the role of ISIS ideology as primary driver of the violence. For example, though Zale Thompson was reportedly inspired in part by ISIS propaganda, an FBI threat assessment on Black Identity Extremism claimed he had tattoos and pocket litter tied to black separatist groups, and a 2017 National Counterterrorism Center report, “Sunni Violent Extremist Attacks in the United States since 9/11,” stated there was no intelligence community consensus on his motive.⁵⁹ Thompson also had multiple run-ins with the law over domestic violence accusations before his attack.⁶⁰

Similarly, four of the 13 attackers had reported mental health issues. At the more severe end of the spectrum, Mahad Abdirahman was ruled to have schizophrenia and had spent most of the year of his attack in a mental institution.⁶¹ Wasil Farooqui reportedly was hearing voices at the time of his attack, was diagnosed with schizoaffective disorder, and had previously been institutionalized.⁶² Edward Archer’s mother claimed he had been suffering from mental health issues and had been hearing voices.⁶³ At the seemingly less severe end of the spectrum, Zale Thompson reportedly struggled with depression and drug use.⁶⁴

With the exception of the attack on the “art contest” in Garland, Texas, where the attackers were in contact over the internet with ISIS operatives abroad, these attacks were inspired attacks in which ISIS and/or other foreign terrorist groups did not play an operational role or provide direction. While the nonlethal attackers used a diverse variety of weapons, eight of the 13 attacks utilized bladed weapons, vehicular ramming, or arson in the case of Tnuza Hassan — methods that may explain their lack of lethality compared to the firearms used by five of the eight lethal terrorist attackers since 2014.

These attacks were inspired attacks in which ISIS and/or other foreign terrorist groups did not play an operational role or provide direction.

While the incident in Garland has been the only ISIS-enabled attack in the United States, there have been several foiled plots in which ISIS’ virtual recruiters sought to encourage and aid attacks.⁶⁵ These include a foiled plan by three men in Boston in June 2015 to attack Pamela Geller, the organizer of the Prophet Muhammad cartoon contest in Garland.

One case in particular that illustrates the danger of ISIS-enabled plots is that of Justin Sullivan. Before his arrest in June 2015, Sullivan plotted with Syria-based ISIS recruiter Junaid Hussain to conduct an attack.⁶⁶ He agreed at Hussain’s behest to make a video of the attack that could be used by ISIS in its propaganda.⁶⁷ The danger that Sullivan posed is emphasized by his conviction for a murder, in which he shot and killed his neighbor.⁶⁸

The conclusion that the threat to the United States is ISIS-inspired and ISIS-enabled, but not ISIS-directed, mirrors the statements of a variety of government officials. In February 2018, Director of National Intelligence Dan Coats testified, “US-based homegrown violent extremists (HVEs) will remain the most prevalent Sunni violent extremist threat in the United States.”⁶⁹ Coats testified similarly in 2017.⁷⁰ In December 2017, FBI Director Christopher Wray testified, “Currently, the FBI views ISIS and homegrown violent extremists as the main terrorism threats to the United States.”⁷¹ In May 2017, Nicholas Rasmussen, then-director of the National Counterterrorism Center, stated: “We certainly know that al-Qa‘ida and ISIS continue to aspire to carry out significant attacks on U.S. soil, but they are challenged to do so.”⁷²

On January 27, 2017, a week after being sworn in as president, Donald Trump signed an executive order instituting a travel ban on foreign nationals from seven majority-Muslim countries: Iran, Iraq, Syria, Sudan, Libya, Yemen and Somalia. The order also halted U.S. entry for Syrian refugees and capped the total number of refugees allowed entry in 2017 at 50,000. As a result of court challenges and international outcry, the ban was narrowed to not apply to those with close family members in the United States. Iraq was also dropped from the list of countries. The revision kept the 50,000-refugee cap in place and put a 120-day freeze on entry of any refugee starting June 29, 2017. Further revisions added Chad to the list and more limited restrictions on travelers from Venezuela and North Korea, and dropped Sudan and eventually Chad. The Supreme Court upheld the third version of the travel ban in a 5-4 decision in June 2018.

The administration justified its travel ban by arguing, “Numerous foreign-born individuals have been convicted or implicated in terrorism-related crimes since September 11, 2001.”⁷³ Yet, the travel ban would not have prevented a single death from jihadist terrorists since 9/11. Nor would it have prevented the 9/11 attacks, which were perpetrated by 15 Saudis, two Emiratis, an Egyptian and a Lebanese citizen — all from countries that are not on the travel ban list.

The threat to the United States is largely homegrown. Eighty-four percent of the 449 individuals tracked by New America and accused of jihadist terrorism-related crimes in the United States since 9/11 were either U.S. citizens or U.S. legal residents.⁷⁴ Just under half of them, 223, were born American citizens. Around a three in ten were converts.

Syrian refugees settled in the United States have not posed a threat, either. No lethal act of jihadist terrorism since 9/11 has been carried out by a Syrian refugee. An ISIS terrorist with any sense is quite unlikely to try to infiltrate the United States as a Syrian refugee. Anne Richard, a senior U.S. State Department official, testified at a Senate Homeland Security Committee hearing in November 2015 that any Syrian refugee trying to get into the United States is scrutinized by officials from the National Counterterrorism Center, FBI, Department of Homeland Security, State Department and Pentagon. Further, Leon Rodriguez, then the director of U.S. Citizenship and Immigration Services, who also testified at the November 2015 hearing, said that of the millions of people who try to get into the United States each year, “Refugees get the most scrutiny and Syrian refugees get the most scrutiny of all.”⁷⁵ This scrutiny can take up to two years.

Eighty-four percent of the 449 individuals tracked by New America and accused of jihadist terrorism-related crimes in the United States since 9/11 were either U.S. citizens or U.S. legal residents.

Every lethal attacker since 9/11 was either a citizen or permanent resident of the United States at the time of the attack, and none came from a country covered by the travel ban. Nine, more than half, of the 15 deadly attackers were born in the United States.⁷⁶

*On March 6, 2017 the Trump administration issued a new executive order, which did not include Iraq in the list of visa restricted countries. On September 24, 2017, the travel ban was revised again to drop Sudan, and add travel restrictions regarding Venezuela and North Korea (not displayed on this map), as well as Chad.

Among the individuals who conducted potentially lethal attacks inside the United States that were foiled or otherwise failed to kill anyone, there are only four cases that the travel ban could have applied to. None provides a convincing argument for the travel ban. In one case, Mohammed Reza Taheri-Azar, a naturalized citizen from Iran, drove a car into a group of students at the University of North Carolina in 2006, injuring nine people.⁷⁷ However, Taheri-Azar came to the United States at the age of 2 with his parents, and according to his older sister spoke no Arabic and only rudimentary Farsi.⁷⁸ He conducted his attack about two decades after arriving in the United States. His radicalization did not occur in Iran but in the United States.

Similarly, Dahir Adan, who committed the stabbing at a mall in Minnesota in 2016, was a naturalized citizen from Somalia, though he was born in Kenya.⁷⁹ Like Taheri-Azar, Adan came to the United States as a young child and his radicalization occurred in the United States, not abroad.⁸⁰

Abdul Razak Ali Artan was a legal permanent resident who came to the United States as a refugee from Somalia in 2014, having left Somalia for Pakistan in 2007. In 2016, at age 18, he rammed a car into his fellow students on the campus of Ohio State University and proceeded to attack them with a knife, injuring 11 people. However, it is not clear that the attack provides support for the travel ban. Artan left Somalia as a pre-teen, and if he was radicalized abroad, it most likely occurred in Pakistan, which is not included in the travel ban. In a Facebook posting before his attack, Artan cited Anwar al-Awlaki, the Yemeni-American cleric born in the United States, whose writings have helped radicalize a wide range of extremists in the United States.

Finally, there’s Mahad Abdirahman, a 20-year-old naturalized citizen born in Somalia, who stabbed and injured two men at the Mall of America on November 12, 2017. During his trial, Abdirahman stated he was inspired by ISIS. However, Abdirahman’s case is far from clear evidence for the travel ban. He had previously been hospitalized for mental illness and was prescribed medication that he had stopped taking. He also faced an earlier assault charge, having stabbed a psychiatrist with a pen.

The Department of Homeland Security’s own analysis from February 2017 undercuts the justification for the travel ban. The DHS report, which was leaked, assessed that “country of citizenship is unlikely to be a reliable indicator of potential terrorist activity” and found that half of the 82 extremists it examined were native-born American citizens. DHS determined that those who were born abroad came from 26 different countries, with no single country accounting for more than 13.5 percent of the total, and that three of the travel ban countries (Iran, Sudan and Yemen) had only one extremist in the assessment who was born there, while there were no individuals from Syria.⁸¹

The DHS report assessed that “country of citizenship is unlikely to be a reliable indicator of potential terrorist activity” and found that half of the 82 extremists it examined were native-born American citizens.

Another leaked DHS report, from March 2017, which examined the origins of 88 foreign-born extremists, assessed that “most foreign-born US-based violent extremists likely radicalized several years after their entry to the United States, limiting the ability of screening and vetting officials to prevent their entry because of national security concerns.”⁸² The report found that about half of foreign-born extremists were younger than 16 when they entered the country and the majority had lived in the United States for 10 years before their indictment or death.⁸³

A report authored by the Cato Institute’s David Bier found only 13 post-9/11 vetting failures in which an individual entered the United States and committed a terrorism-related crime after 9/11.⁸⁴ The report also found that the rate of vetting failure was 99.5 percent lower following 9/11 and the resultant reforms to immigration security, despite using a broad definition of vetting failure.

Only one vetting failure identified by the Cato study, which covered the period from 2002 through 2016, involved a deadly attack — a rate of one for every 379 million visa or status approvals.⁸⁵ That failure was the entry of Tashfeen Malik, who conducted her attack alongside her husband, a natural-born U.S. citizen who had already acquired the weapons used in the attack and plotted violence before her entry. In addition, Malik was born in Pakistan and would not have been covered by the travel ban.

This does not mean the system is perfect. In August 2018, the United States arrested Omar Ameen, a 45-year-old Iraqi who had come to the United States as a refugee, in order to extradite him to Iraq where he faced charges for a June 22, 2014, murder of a police officer in support of ISIS. According to court records, Ameen had been a member of ISIS and its precursor groups since 2004 and faced two prior warrants for arrest before he entered the United States.⁸⁶ His entry represents a relatively major failure of the system that requires review. However, the court documents do not refer to any terrorist plotting within the United States, and the vetting failure in Ameen’s case is a rarity among the terrorism cases involving U.S. persons.

The Trump administration has marshalled its own politicized and highly misleading data to justify the travel ban and its immigration and border security-centric counterterrorism effort. A joint report by the Justice and Homeland Security departments in January 2018 asserted that “Three Out of Four Individuals Convicted of International Terrorism and Terrorism-Related Offenses were Foreign-Born.”⁸⁷

The DOJ-DHS report is highly misleading.⁸⁸ First, even taking the report at face value, it suggests that the threat is largely homegrown, with a majority of cases being citizens and a quarter being natural-born citizens. Second, the report includes among the international terrorism cases it examines numerous examples of individuals extradited to the United States, who are simply not immigrants. Though the exact data underlying the report is not available, by some accounts it may include as many as 100 cases of individuals who were extradited.⁸⁹ In addition, by using international terrorism cases, the report excludes domestic terrorism cases — particularly those motivated by far-right and similar ideologies — yet this cannot be justified by focusing on the jihadist threat, as the report includes cases involving the FARC and other non-jihadist groups. Third, the report assumes that naturalized citizens are meaningfully distinct from natural-born citizens and represent a border security issue, without providing evidence. In fact, as the aforementioned leaked DHS reports show, this is at odds with DHS’ own findings in other reviews of the data. White House adviser Stephen Miller sought to explicitly include language emphasizing the threat from children of foreign born citizens in the report, a goal that DHS Secretary Kirstjen Nielsen reportedly objected to because it was unsubstantiated.⁹⁰ Fourth, the report looks only at federal convictions for terrorism-related crimes and thus misses multiple important cases of U.S.-born citizens including Omar Mateen, who died conducting the Orlando attack; Carlos Bledsoe, who was charged with murder in state court for his 2009 attack on a military recruiting station in Arkansas; and Nidal Hasan, an Army major and psychiatrist who was charged in military court for his attack on Fort Hood in Texas.

Today’s extremists in the United States radicalize online, and the internet knows no visa requirements. Just under half of the jihadists charged in the United States since 9/11 either maintained a social media account where they posted jihadist material or interacted with extremists via encrypted communications; in recent years, an active online presence has been almost universal among American jihadists.⁹¹

The attack in Garland, Texas, described in detail above, is a case in point. Not only were the perpetrators both native-born American citizens who would not have been stopped by the travel ban, but their interlocutors from ISIS did not set foot in the United States, instead encouraging the plot through online communication. The travel ban does nothing to respond to the most likely threat today: ISIS-inspired and ISIS-enabled homegrown attacks.

The threat posed by American “foreign fighters” returning to the United States is quite limited. To date, no one who fought for ISIS or other extremist groups in Iraq or Syria has committed an act of terrorism in the United States after returning, according to a review of cases conducted by New America.

Of the few Americans who have fought with militant groups in Syria and returned, only one, Abdirahman Sheik Mohamud, conspired to carry out an attack. Mohamud, a Somali-American, traveled to Syria to join the Nusra Front in April 2014, only three months after he became a naturalized citizen. He returned to the United States that June and shortly thereafter communicated with an unnamed individual about his desire to travel to a military base in Texas and kill three or four U.S. soldiers.⁹² Mohamud was arrested in February 2015 — before attempting to carry out this plot — and pleaded guilty to material support charges in June 2017.

Today’s extremists in the United States radicalize online, and the internet knows no visa requirements

This conclusion is shared by a February 2018 report from George Washington University’s Program on Extremism, which stated, “Only one of the 12 returnees identified in this study returned with the intent to carry out an attack on behalf of a jihadist group in Syria.”⁹³

The threat from returning foreign fighters should of course be an area of focus for U.S. Customs and Border Protection officials and those in the intelligence and law enforcement communities tasked with protecting the homeland.

The terrorist threat in the United States does not emanate only from individuals motivated by jihadist ideology. The broader challenge is from individuals who plan and commit political violence motivated by a range of ideologies, including far-right, black nationalist and left-wing causes, as well as idiosyncratic notions.

New America has found that since 9/11, individuals motivated by far-right ideology and/or belonging to organizations with such motivations have killed 73 people in the United States, while individuals motivated by black nationalist or separatist ideology have killed eight people.⁹⁴

Since Donald Trump assumed the presidency, the United States has seen three deadly jihadist attacks: the shooting committed by Joshua Cummings in January 2017, the October 2017 vehicular ramming attack by Sayfullo Saipov, and the March 2018 stabbing by Corey Johnson. There have also been six lethal far-right-wing attacks. Four of these attacks have very clear political motivations, while two feature individuals with known extremist ties and beliefs who may have been motivated by personal issues rather than political ideology.

• On March 20, 2017, James Harris Jackson killed an African-American man with a sword in New York City after traveling from Baltimore for that purpose.⁹⁵ Jackson was indicted on a rare state terrorism charge.⁹⁶ Jackson had liked alt-right YouTube videos and written an anti-black manifesto before his attack.⁹⁷
• On May 20, 2017, Sean Urbanski attacked and killed an African-American man who was visiting the University of Maryland.⁹⁸ Prosecutors initially did not assert that Urbanski had a racial or political motive, despite his belonging to a white supremacist Facebook group titled Alt Reich: Nation. However, in October 2017, prosecutors charged Urbanski with a hate crime in relation to the attack based on digital evidence from his computer.
• On May 26, 2017, Jeremy Christian, a 35-year-old active in violent right-wing “free speech” protests in Portland, Oregon, stabbed and killed two men who intervened when he was harassing two Muslim women on public transit.⁹⁹ During a court hearing, Christian declared, “Death to the enemies of America. Death to antifa [anti-fascists]. You call it terrorism. I call it patriotism. Die.”¹⁰⁰
• On Aug. 12, 2017, James Alex Fields Jr., a 20-year-old from Maumee, Ohio, rammed his car into a group of people in Charlottesville, Virginia, who were gathered to protest a white nationalist rally, killing a 32-year-old woman and injuring 19 others.
• In January 2018, prosecutors in Orange County, California, charged Samuel Woodward, a 20-year-old man, with stabbing and killing Blaze Bernstein, an openly gay and Jewish former classmate of his.¹⁰¹ Woodward was a member of Atomwaffen Division, a neo-Nazi group, although investigators caution that his membership in the group may not have motivated the attack.¹⁰² In August 2018, prosecutors added a hate crime enhancement to the accusations, alleging that Woodward killed Bernstein because he was gay.¹⁰³
• In July 2018, Ronald Lee Kidwell, a 47-year-old white man, was charged with the murder of MeShon Cooper, a 43-year-old black woman, whose body was discovered in a suburb of Kansas City, Kansas, after she was reported missing in early July. According to his family and neighbors, Kidwell held white supremacist views, bragged of being a member of the KKK, displayed the Confederate flag, and according to his daughter had a history of targeting black people for violence (he had previously pleaded guilty to assault in a 2011 case where the victim was also a black woman).¹⁰⁴ According to court documents, Kidwell told law enforcement that he killed Cooper after an argument escalated, claiming she threatened to reveals his HIV-positive status.¹⁰⁵ Law enforcement officials have not determined whether the murder was a hate crime and are still investigating.

In addition to the above attacks, on October 1, 2017, Stephen Paddock killed 58 people in a shooting at an outdoor music festival in Las Vegas. Paddock’s motive remains unclear, but witness statements released by law enforcement following a lawsuit include comments that suggest Paddock held conspiracy and anti-government views characteristic of the far right, and one witness claimed that Paddock told him, “Somebody has to wake up the American public and get them to arm themselves.”¹⁰⁶ The Las Vegas Police Department closed the investigation without determining a motive.¹⁰⁷

If the Las Vegas shooting was an anti-government terrorist attack, it would be the deadliest post-9/11 terrorist attack motivated by any ideology in the United States. It would also mean that far-right terrorist attacks have killed 131 people in the United States since 9/11, surpassing the death toll from attacks motivated by jihadist ideology.

The United States has also seen one deadly attack by an individual motivated by black nationalist ideology since Trump assumed office.¹⁰⁸ On April 18, 2017, Kori Ali Muhammad, a 39-year-old African-American man, was arrested and charged with killing three people in a shooting in Fresno, California.¹⁰⁹ Police said race was a factor in the murders and Muhammad’s social media presence included black nationalist posts. Muhammad’s father said his son believed he was part of a war between whites and blacks and that “a battle was about to take place.”¹¹⁰

If the Las Vegas shooting was an anti-government terrorist attack, it would be the deadliest post-9/11 terrorist attack motivated by any ideology in the United States.

There have also been nonlethal acts of political violence. In August 2017, an explosive device was thrown into the Dar Al-Farooq Islamic Center in Bloomington, Minnesota, though no one was injured.¹¹¹ In March 2018, a federal grand jury indicted three men, who were part of an anti-government militia, in relation to the bombing as well as an attempted bombing of an Illinois abortion clinic.¹¹²

The shooting attack by 66-year-old James T. Hodgkinson on Republican congressmen during a June 2017 baseball practice in Alexandria, Virginia, which did not kill anyone but injured multiple people including Representative Steve Scalise, the number three House Republican leader, suggests that political violence could again be emerging on the left.¹¹³

The United States has also seen serious foiled domestic terrorism plots. For example, in April 2018, three men were found guilty of plotting to bomb an apartment complex in Garden City, Kansas, that was home to the local Somali community.¹¹⁴ Prosecutors said the men were part of a militia and had written a manifesto, while Attorney General Jeff Sessions called the guilty verdict “a significant victory against domestic terrorism and hate crimes.”¹¹⁵ In May 2018, FBI Director Christopher Wray testified that the FBI had 1,000 open domestic terrorism investigations, a number similar to the 1,000 ISIS-related investigations the FBI says it has open.¹¹⁶ In July 2018, Miami Beach police arrested Walter Edward Stolper, a 72-year-old who had recently been served with eviction papers.¹¹⁷ According to police, Stolper planned to burn down his building, sought to target Jews specifically and had Nazi material in his apartment. Police stated, “Already in the building he had disposed of eight additional gas canisters down the trash chute from the 15th floor,” adding, “We were minutes away from a potentially deadly situation.”¹¹⁸

This violence takes place alongside public violence by individuals who are motivated not by a traditional, formal political ideology, but rather in response to the broader polarization and conspiracy theorizing affecting American political discourse, as well as by the amplifying role social media can play. In April 2018, Nasim Aghdam, a 29-year-old woman, shot and injured three people at YouTube’s headquarters in California before killing herself. According to police, Aghdam was upset at YouTube for policies she considered to be harming her effort to build an audience for her channel, where she expressed a range of views on a variety of issues.¹¹⁹ Similarly, in December 2016, a man fired a weapon inside a pizzeria in Washington, D.C., because he believed a conspiracy theory that the restaurant was in fact a secret front for a child sex ring run by senior Democratic Party officials.¹²⁰ No one was wounded in that attack.

However, there is great potential for violence motivated by conspiracy thinking to turn into more clearly political violence. For example, Matthew Wright, 30, was charged with terrorism crimes for a standoff near the Hoover Dam on June 15, during which he blocked traffic with an armored car and an AR-15 rifle. He wrote letters to President Trump and other officials that included references to the QAnon conspiracy, which itself has a political framing that pits Trump as a hero fighting a conspiracy of the “deep state” and elites.¹²¹

This violence from political and nonpolitical motives other than jihadism emphasizes the need to address non-jihadist ideologies as well as warns against an overemphasis on ideology as a factor amid a larger range of public violence facing the United States today.