Today's Terrorist Attack Doesn't Show that Foreign-Born Attackers Are a Major Threat

It was lower during Biden's administration

Mohamed Bailor Jalloh murdered one person and injured two others in a terrorist attack yesterday at Old Dominion University in Virginia. I immediately knew that Jalloh’s attack was motivated by Islamism because I knew of him from my earlier research on foreign-born terrorism. I listed Jalloh in my 2025 policy analysis on foreign-born terrorism as convicted of planning an attack in 2016 (see appendix), which he did as a naturalized immigrant from Sierra Leone. He was released from jail and then committed his recent attack in Virginia.

Jalloh’s dastardly attack is one of five deadly foreign-born terrorist attacks during the second Trump administration that have killed a total of eight people. Six of them were victims of foreign-born terrorists motivated by Islamism, two by a right-wing terrorist who killed his parents to steal money to pursue his plot to assassinate President Trump to start a white supremacist ethnostate. In comparison, a single foreign-born terrorist killed one person during the Biden administration, and he was motivated by Chinese nationalism.

Figure 1 shows the number of victims of foreign-born terrorism. It’s easy for the number of victims to vary so much over just a few years when there are so few. The number of victims of foreign-born terrorism in 2025 was the highest since 2017, when Trump was also in office, but just 0.03 percent of homicides last year were committed by foreign-born terrorists in attacks. The annual chance of being murdered in a foreign-born terrorist attack during the second Trump administration is about one in 85 million per year, about 16 times higher than during the Biden administration so far, which was about one in 1.3 billion per year. Regardless, it’s a tiny risk even though fewer people were murdered in foreign-born terror attacks during Biden’s presidency than any other president since Gerald Ford and likely even earlier.

Over 85 percent of all people killed by terrorists in attacks on US soil were killed by foreign-born terrorists since 1975. The 9/11 attacks account for 83 percent of those victims because they were the deadliest terrorist attacks in world history by a factor of nine.[i] Things have changed since 9/11, which occurred smack dab in the middle of my dataset.

More people have been killed in terrorist attacks committed by native-born Americans since 9/11 than by foreign-born terrorists, and it’s not close (Table 1). Native-born terrorists murdered 6.3 people in attacks for every one person murdered by a foreign-born terrorist. Of the 335 people murdered in terrorist attacks on US soil since September 12, 2001, 289 were murdered by native-born Americans and 46 by foreign-born attackers. The share of victims in foreign-born attacks is 13.7 percent, almost exactly their average share of the US population since 2001.

What does all this mean? Jalloh didn’t survive his attack, but terrorists who do should be prosecuted and punished to the fullest extent of the law. Keeping foreign-born terrorists out of the United States is a legitimate function of government that nobody disputes. But the data are clear that foreign-born terrorism is a tiny risk, even during the periods when it is most elevated, and each attack is committed by a handful of ideologically motivated killers who are wildly unrepresentative of the tens of millions of foreign-born people living peacefully in this country. Punishing innocent immigrants and people abroad who want to come to this country, launching more foreign wars, or stripping Americans of civil liberties in response to attacks this rare would be an expensive overreaction that would cost far more than any benefits.

---

[i] If you count the 10/7 attack in Israel as a terrorist attack, then 9/11 was two-and-a-half times deadlier than the next deadliest attack, but some don’t count Hamas’ attack because Hamas was the government of Gaza and therefore their attack is not terrorism by definition. Brutal, regardless of how you classify it, but plausibly not terrorism.