The CP fails – terrorists are too innovative, and it can’t stop individual terrorists.

The resources of intelligence and law enforcement will likely be increasingly strained trying to identify and prevent simple, crude terrorist attacks using everyday weapons that require little planning and do not depend on terrorism’s conventional arsenal. Conversely, additional challenges will continue to be presented by the deliberate efforts of a range of adversaries to obviate existing laws and restrictions on weapons through 3D-printing technology and “ghost guns.”

Terrorists are utilizing a spectrum of both simple and innovative weapons to carry out attacks that in some cases minimize planning and logistical preparation and in others effectively render national laws and restrictions on firearms irrelevant. The stabbing, mass shooting and vehicular attacks detailed above are clearly less sophisticated and their perpetrators less capable than their more professional, trained counterparts—such as the multiple Islamic State teams that executed the Paris November 2015 and Brussels March 2016 attacks, largely with sophisticated suicide vests. Nonetheless, they can be just as homicidal. A particular case in point is the truck driven into a crowd of Bastille Day celebrants in Nice in July 2016, which killed 86 persons. Although the death toll from Minassian’s Toronto vehicular rampage was considerably lower, it was no less tragic and underscored the homicidal potential of ramming attacks against archetypal soft targets.

Last fall’s shootings in Halle, Germany, showcased an early—albeit not entirely successful—use of 3D-printing technology for firearms. Stephan Balliet’s manifesto included detailed descriptions of an array of homemade guns and explosives, and cited his primary aim as to “prove the viability of improvised weapons.” Balliet alarmingly also turned his attack into a didactic exercise, likely eschewing the more numerous casualties he could have inflicted using proven, off-the-shelf weapons by instead utilizing a number of homemade guns in order to encourage others to improve on his designs and thereby produce more effective firearms in the future. As Daveed Gartenstein-Ross, Colin Clarke, and Matt Shear have noted, Balliet’s struggles do not diminish the threat posed by 3D-printed arsenals—terrorists implementing new technologies often experience difficulties, but, “after an initial period marked by failure, [violent non-state actors] often get far more proficient, posing a host of dangers that governments move to counter only belatedly.”

In addition to the promise of 3D-printing technology, it is also easy—as a recent New York Times exposé reveals—to evade national firearms laws and restrictions with so-called “ghost guns”: weapons without serial numbers or sales pedigrees that are assembled from kits purchased online. Steven Carrillo, an anti-government extremist who murdered two police officers in California in two June 2020 incidents, used a ghost gun without a serial number to commit the killings. And the aforementioned Canadian white supremacist, Patrik Mathews, was ultimately arrested along with two American far-right extremists on weapons charges after they allegedly built a homemade assault rifle.

There has also been an evolution in terrorist targeting. Largely behind us are the days when terrorists focused on organizing elaborate plots aimed at well-defended and clearly symbolic hard targets, such as embassies, airports, military installations and government offices. Today’s terrorists sacrifice the spectacular for the straightforward. In a now well-established pattern, lone actors of all ideologies attack soft targets—public venues and other gathering places—where their inherent open access inhibits effective defenses and thereby lowers the bar in terms of operational planning and execution. They have increasingly provided a new challenge for law enforcement and politicians alike, not least in how to better defend locations often defined by their openness and accessibility.