Over the past 20 years, Americans and the West have witnessed many radical Islamic terrorist attacks, from those in New York and Washington on Sept. 11, 2001, Madrid in March 2004, and London in July 2005 to those in Paris, San Bernadino, and Orlando in the past year. All these attacks in the United States and Europe have one thing in common: They have all been carried out by walk-in volunteers.

America is less safe today than last Friday. The reason is President Donald Trump’s ban on citizens and refugees from seven predominately Muslim countries. This ban gives unprecedented life to the worst jihadist narrative — the idea that the West has declared war on Muslims. This narrative is not just talk. It is the principal catalyst for ISIS and other radical Islamic terrorist groups’ ability to carry out attacks that kill Americans.


Although we are often fascinated with terrorists’ creative use of ordinary tools like box cutters and hidden explosives like underwear bombs, by far their greatest resource to do us harm is simply the fighters themselves. Without the willingness of individuals to conceive, plan, and execute attacks, all the rest is simply a pipe dream. This is why the best measure of the power of al Qaeda, ISIS, or any terrorist group is simply the number of individuals willing to attack.

Why do these attackers volunteer? By far, the number one reason is the propaganda narratives in the militant groups’ videos, audiocassettes, and printed material.

For over 15 years, I and my research team at the Chicago Project on Security and Threats have studied every one of the over 5,000 suicide terrorist attacks around the world since 1980 and many non-suicide terrorist attacks as well. Without doubt, the 9/11 hijackers, Madrid and London bombers, and attackers in Paris, San Bernadino, and Orlando were not the products of years of brainwashing in madrassas or coercion through kidnapping. Nor are they generally from poor families, unemployed, or from poor educational backgrounds. Indeed, over half of the transnational Islamic terrorists in all the major attacks in the United States and Europe are working or middle class with college education.


What motivates them to strike in the West is that they are inspired by the idea of responding to Muslim communities under threat from the West. How do we know? They say so.

Here are the words to the British public in the last video will testimonial of Mohammad Sidique Khan, the leader of the London bombers:

“Your democratically-elected governments continuously perpetuate atrocities against my people all over the world. And your support of them makes you directly responsible — just as I am directly responsible for protecting and avenging my Muslim brothers and sisters. Until we feel security, you will be our targets, and until you stop the bombing, gassing, imprisonment, and torture of my people, we will not stop this fight. We are at war and I am a soldier.”

For transnational Islamic attackers, what drives them is not mainly promises of virgins or other heavenly benefits, but the idea that they are defending Muslims under siege. And the leaders of radical Islamic terrorist groups know that this is their best appeal to mobilize volunteers to attack us. How do we know? The leaders say so.

Over and over, ISIS leaders repeat the narrative that America and the West are indifferent to the atrocities of Muslims and carry out policies that actively harm Muslim societies as a centerpiece of the group’s recruitment propaganda. For example, on May 23, 2016, Abu Mohammad al Adnani, the architect of ISIS’ progaganda machine, said:


“Where are the Kafir West’s alleged defense of ‘civilians’ and protection of ‘human rights’ and ‘freedom’? … The sentiments in Europe, America, and other disbelieving nations are not moved nor shaken by the displacement of millions. They are not disturbed by the hunger, disease, suffering, and death of thousands of helpless and besieged children, women, and elderly people. … The people of Europa and other lands of Kafir do not shudder at the Russian destruction of hospitals and residential zones, though they are afflicted by sleeplessness and insanity whenever the Islamic State decapitates some of its disbelievers, causing them to shiver, tremble, flare up, bombard, and rally.”

And here is how Dabiq, ISIS’ online magazine, justified the execution of James Foley:

“The US had killed women, children, and the elderly, during its direct occupation of Iraq prior to its withdrawal. There are countless accounts of American soldiers executing families and raping women under the sanctity of the US military and Blackwater. Muslim families were killed under the broad definition of ‘collateral damage,’ which the US grants itself alone the right to apply. Therefore, if a mujāhid kills a single man with a knife, it is the barbaric killing of the ‘innocent.’ However, if Americans kill thousands of Muslim families all over the world by pressing missile fire buttons, it is merely ‘collateral damage.’”


Trump’s ban on Muslims as a category fits precisely the stereotype of America and Americans that al Qaeda, ISIS, and other Islamic groups have used for decades to inspire attackers to kill us. Every Muslim family unfairly detained at an airport, every Muslim who worked for the United States and is returned to face persecution or death, and every statement that privileges Christians over Muslims does much more to inspire Islamic terrorism than militant propaganda alone. These American acts are the realities that gives ISIS propaganda teeth, because they go the heart of the moral code attributed to us.

Does America have a right to defend itself against Islamic terror? Of course we do.

The right of self-defense, however, does not mean that any act taken in the name of self-defense actually makes us safer. Iraq, Syria, Iran, Libya, Somalia, Sudan, and Yemen combined have a total of approximately 220 million Muslims. As of now, far more citizens in these countries are working with America and the West to oppose ISIS than have joined the group. Accordingly, any blanket ban against Muslims from those countries not only helps ISIS recruit more, but also to gain power that could turn the tables in its favor.

Trump should immediately rescind the travel ban until there is a plan that actually makes America safer.

Robert A. Pape is professor of political science and director of the University of Chicago Project on Security and Threats, and author of numerous books and publications on terrorism.