IMMIGRANTS & TERRORISMAlarmism about Terrorism Is Risky and Unjustified
The annual chance of being murdered in an attack committed by a foreign-born terrorist is about one in 4.5 million—about 323 times lower than the chance of being murdered in a normal homicide during that 1975–2023 timeframe. The U.S. ought to be more realistic about the foreign-born terrorist threat. Alarmism in the face of small and manageable risks that probably haven’t arisen is a tremendous vice that policymakers should avoid.
In their recent Foreign Affairs article “The Terrorism Warning Lights Are Blinking Red Again,” Harvard professor Graham Allison and former acting CIA director Michael J. Morell (henceforth A&M) argue that signs of imminent terrorist attacks on the U.S. are as strong now as when CIA director George Tenet warned about them before the 9/11 attacks. “Given the stakes, complacency is a greater risk than alarmism,” A&M reason. “Simply put,” they claim, “the United States faces a serious threat of a terrorist attack in the months ahead.”
A&M paint an ominous picture, but a reasonable level of concern is better than alarmism or complacency. Attacks on U.S. soil committed by terrorists who crossed the southern border are a possibility, but the wisest options are not to do nothing or to panic. There is an entire spectrum of concern between those routes that policymakers and the public should embrace. Terrorism is uncommon and difficult-to-impossible to predict, and—with some dramatic exceptions—it inflicts small amounts of damage the overwhelming majority of the time.
We agree with A&M when they argue that “assessments of national security threats must account for both the level of risk and the scale of potential consequences.” But we disagree with their conclusion that “in the case of terrorism, both should compel the administration to take action.” Their conclusion results from an incomplete assessment of the risks and costs of terrorism emanating from across the southern border and a disregard for the costs of alarmism—financial or otherwise. To recap the past 20-plus years, hysteria over terrorism resulted in violations of civil liberties, ethnic profiling, multiple foreign invasions, trillions of dollars spent on counterterrorism and trillions more in wealth generation forgone from increased restrictions on immigration in response to the alarmism to which A&M are asking us to return. To devise the smartest approach to limiting the foreign-born terrorist threat, we must ensure we’re getting the most accurate picture of this risk that we possibly can.
A Minuscule Possibility
Understanding the base rate of foreign-born terrorism in the United States is the best starting point for calculating that risk, but A&M totally neglect the base rate. Also known as a prior probability, the base rate is how common an event is within a certain dataset before taking any new information into account. Analysts need a base rate as a starting point to understanding how likely terrorism is, which they can then adjust with new evidence.
