Two major public events made a lasting impression on me as a child. The first was the 1992 Los Angeles riots. We had moved out of Burbank 18 months before, but my mind was still on Burbank and LA generally. I remember watching the riots on TV and listening to adults talk about them, especially those who remembered the 1965 Watts riots and had their own stories of dealing with LAPD officers. The second major event was the 9/11 attacks, which occurred right before my 18th birthday during my senior year in high school. Nobody who watched the towers come down live on the news will forget it.
In the decades since, the country certainly hasn’t forgotten 9/11 – and for good reason. The 9/11 terrorist attacks were the deadliest in world history – by a factor of four or nine, depending on how expansive a definition of terrorism you use. The resulting domestic surveillance, overseas wars, and immigration restrictions have shaped much of politics to this day.
To understand how big a threat terrorism is and the potential hazard some immigrants and other foreign‐born individuals pose to the United States, the Cato Institute released a new paper today, Terrorism and Immigration: A Risk Analysis, 1975–2022. The report analyzes the number of foreign‐born terrorists, the murders they committed in their attacks, and other information about them for 1975–2022. This new Cato policy analysis is an update of earlier papers on the topic.
In sum, the report shows that the chance of being killed by a foreign‐born terrorist in the U.S. is about 1 in 4.3 million per year, a very low‐probability event. For comparison, the annual chance of being the victim of a regular criminal homicide in the U.S. is 1 in 20,134, a much higher probability.
Terrorism is the threatened or actual use of illegal force and violence by a non‐state actor to attain a political, economic, religious, or social goal through coercion, fear, or intimidation. It is a specific form of crime that often garners more media and political attention than its impact would seem to deserve. That may be because many Americans vastly exaggerate the scale of terrorism, as some polls suggest. Or it may be due to the nature of the crime, where the unpredictability of terrorism and its motivations are scarier.
Yet another theory says Americans see the victims of terrorism as more worthy of protection than the victims of normal criminal homicide and other crimes, suggesting that the government should do more to prevent those victims from being harmed.
Our analysis shows that between 1975 and 2022 some 219 foreign‐born terrorists planned, attempted, or carried out attacks that ultimately killed 3,046 people (Table 1). They also injured 17,077 people, with a chance of being injured of about 1 in 774,000 per year (Table 2). For murders committed during terrorist attacks, 98 percent occurred during 9/11. In terms of injuries, 87 percent occurred on 9/11.
Zero Americans were killed in domestic attacks committed by foreign‐born terrorists in 30 of the 48 examined years. In 29 of the 48 years covered by the new Cato paper, zero Americans were injured in attacks committed by foreign‐born terrorists. Islamists were responsible for 99.4 percent of the murders in foreign‐born terrorist attacks and 95 percent of the injuries, followed by a small number of terrorists inspired by right‐wing ideologies and foreign nationalist ideologies. Zero people were killed by terrorists who entered as illegal immigrants.
The federal government should continue to screen foreign‐born terrorists from the flow of people seeking to enter the United States, as it should continue to filter out criminals, spies, and other security threats. However, the government should allocate resources to this endeavor using a cost‐benefit test and not pass broad restrictions on immigrants to allegedly reduce the cost of terrorism. Foreign‐born terrorism is a hazard to the lives and property of Americans. But it is a hazard that can be addressed by not expending further resources and by cutting some existing ones.