Instrument Of Terror

Until the deadly shooting of 14 people in San Bernardino, California, last year by a married couple with a history of privately expressing support for Muslim terrorist groups, most fears of terrorism on U.S. soil had centered on the potential for plane hijackings or biological or chemical weapons. Because of how politicians and the news media have tended to define terrorism since 9/11, guns had rarely entered the conversation.

Part of this is because gun deaths resulting from terrorism are relatively rare in the U.S. Terrorists — as defined by the Global Terrorism Database, a project based at the University of Maryland that is the best source on the subject — shot and killed 82 people in the U.S. from 2002 to 2015.1 That represents 81 percent of all people killed by terrorists in the country in that period. But terrorists kill just a tiny fraction of the more than 33,000 people who die each year in the U.S. from gunfire. Put another way, just one in every 3,400 gun homicides in the U.S. from 2002 to 2014 occurred in a terrorist attack.2 That made the U.S. gun death problem very different from the rest of the world’s: At least one of every 40 people gunned down outside the U.S. over that period died in a terrorist attack.3

But in 2015, four of the seven mass shootings that took place in the U.S. were committed by terrorists: in San Bernardino; at a black church in Charleston, South Carolina; at a Planned Parenthood facility in Colorado Springs and at a Chattanooga, Tennessee, military recruitment center.

Then came the gun massacre at an Orlando gay night club last month that killed 49 people — the deadliest terrorist attack in the country since 9/11. The suspect pledged allegiance to the Islamic State during the attack, placing concerns about the potential for terrorists to obtain guns and to use them in mass shootings front and center. And last week, the suspect in a shooting of 14 police officers in Dallas, five of them fatally, told police negotiators he specifically wanted to kill white police officers, according to the Dallas Police Department, which means the shooting likely fits the Global Terrorism Database’s criteria for terrorism.

That has yet to be determined, but the Orlando and Dallas attacks seem to epitomize the convergence of mass shootings and terrorism in the U.S.: What’s called a terrorist attack and what’s called a mass shooting are increasingly the same. That means attempts to prevent deaths from one kind of attack are also attempts to stop the other. Unfortunately, we don’t really know how to stop either one.

There is no universally accepted definition of terrorism. We don’t always have much information about a shooter’s goals. We’re following the Global Terrorism Database’s count of terrorist attacks, which requires that an attack meet three criteria: (1) that it is intended to achieve a “political, economic, religious or social goal”; (2) that it is intended to deliver a message to people other than its victims; and (3) that it occurs “outside the context of legitimate warfare activities.”4 By this definition, the 2012 shooting that killed 26 people at Sandy Hook Elementary School, which was certainly terrifying, was not terrorism.

Also by this definition, none of the 26 mass shootings compiled by Mother Jones magazine between 1982 and 1998 was committed by terrorists, according to the Global Terrorism Database.5 Just three of the 45 mass shootings from 1999 to 2014 were terrorist attacks: at Columbine High School in 1999, at Fort Hood in 2009 and at a Sikh temple in Oak Creek, Wisconsin, in 2012. (Columbine is considered a borderline case; mental-health experts who reviewed the shooting determined that the attackers’ primary goal probably was to create national terror, unlike in some other school shootings.)

But since the start of 2015, at least half of mass shootings have been terrorist attacks, a major shift from just two years ago.

Lumping these attacks under “terrorism” doesn’t make them easier to address. The attackers have a wide range of aims: Some support Muslim terrorist groups while others are prejudiced against black people or members of specific religious groups. Lone attackers may act independently even when they say they are inspired by terrorist groups, and in the U.S., the easiest weapon for them to obtain that can kill many people quickly is often a gun.

Democrats in Congress have pushed for legislation aimed at reducing terrorists’ access to guns, but their proposals rely on existing lists of suspected terrorists, which exclude many of the suspected shooters in recent terrorist attacks and include many people with no links to terrorism. None of the bills they backed has passed, nor have bills backed by some Republicans that take a similar approach, putting weaker gun-buying restrictions on people included on the lists.

No one quite knows how to address these twin problems, though other countries have tried. What is clear is that any measures aimed at preventing terrorism gun deaths in the U.S. would likely need to tackle mass shootings, too.


  1. The Global Terrorism Database is maintained by the National Consortium for the Study of Terrorism and Responses to Terrorism. We include all terrorist attacks in which the attackers used at least one gun; sometimes, like in San Bernardino, firearms are used along with other weapons. We are not counting the deaths of the perpetrators of terrorist attacks. ^
  2. We’re using data through 2014 because 2015 homicide data isn’t yet available. ^
  3. That’s likely an underestimate because the terrorism data before 2012 may be missing some cases; the database methodology changed in 2012 to find more cases. Erin Miller, program manager for the database, said it is mostly complete for the U.S. back to 1970. Global gun-homicide death data is based on estimates for deaths from assault by firearm for 2005, 2010 and 2013 from the Institute for Health Metrics and Evaluation’s Global Burden of Diseases, Injuries and Risk Factors Study. U.S. gun-homicide deaths come from the Centers for Disease Control and Prevention’s Multiple Cause of Death database. ^
  4. Some attacks in the database, including the Columbine shooting, come with some uncertainty as to whether they meet one or more of the criteria; we’ve included these in the analysis. ^
  5. Mother Jones defines mass public shootings as ones in which the shooting occurred in a public place and isn’t gang-related. Through 2012, it counted only incidents in which at least four people other than the shooters died. Since 2013, it has lowered the threshold to three deaths other than the perpetrators, based on new federal standards for investigating mass shootings. Another major count of mass shooting deaths differs slightly from Mother Jones, particularly in the 1980s and 1990s, but it, too, includes almost no terrorist incidents until recent years. ^