As details emerge about the alleged perpetrators of the Boston Marathon bombings, observers are increasingly speculating that the attacks represent a growing threat of homegrown Muslim terrorism in the United States. Certainly, the reported professions by Dzhokhar Tsarnaev that he and his older brother, Tamerlan, were motivated by jihadist causes, as well as evidence that that they had viewed militant Islamist propaganda, are disturbing. Yet, any claim that their alleged involvement in the bombings portends a growing threat of homegrown terrorist attacks in the United States is greatly exaggerated. There is little basis for thinking that the United States should fear an onslaught of attacks by Muslim jihadists in the United States.
Consider the pattern of Muslims arrested on terrorist-related charges in the United States since the attacks of Sept. 11, 2001. From 2002 to 2008, annual arrests of suspects charged with terrorist-related offenses ranged from nearly two dozen in 2003 to fewer than five in 2008. In 2009 the number of arrests spiked to more than 40.
Analysts and political officials began to warn that we were finally witnessing the insidious effects of Al Qaeda’s propaganda on American Muslim citizens and residents. The 2009 arrests were cited as evidence that homegrown terrorism was emerging as a serious threat. In 2010, however, the number of terrorism-related arrests fell, only to decline further in 2011, and then again in 2012. In retrospect, the 2009 spike could be explained by several unrelated factors, including the clustering of arrests of individuals long suspected of having militant sympathies and the phenomenon of groups of Somalis, primarily from Minnesota, seeking to travel to the Horn of Africa to join the militant group al-Shabaab.
Among jihadist-inspired militants who have plotted against Americans in the United States, more than two-thirds have been foiled at the early planning stages, often by informants or as a result of tips or mistakes made by the bombers themselves. Those who have pursued full-blown plots, identifying targets and developing plans, have done so often in the context of FBI sting operations, in which special agents and informants regularly acted as sympathizers or coconspirators and provided (fake) weapons and financial support.
Only a few lethal attacks have been perpetrated by homegrown terrorists in the United States since 9/11. Analysts generally count two of these as clear-cut cases of jihadist-inspired terrorism. The first was the 2009 shooting at Fort Hood by US Army psychiatrist Major Nidal Hasan. The second, lesser-known attack involved a shooting outside an Arkansas armed services recruiting center by Abdulhakim Muhammad, an African-American Muslim convert.
The capabilities of would-be jihadist terrorists living in the United States are also limited. Since 9/11, with the possible exception of the Boston attacks, Muslim homegrown jihadists have not exploded a single bomb in the United States. There have been two serious efforts to build bombs, both of which involved potentially more sophisticated and deadly explosives than those detonated on April 15. In 2009 Najibullah Zazi plotted to plant explosives on the New York subway system. The following year, Faisal Shahzad tried to detonate a car bomb in Times Square. Although both Zazi and Shahzad had received overseas explosives training, they still failed to fabricate viable explosive devices. Although the Boston bombings were devastatingly lethal given the crowded venue, the fact that the Tsarnaev brothers allegedly used unsophisticated devices — the instructions for which are available on the Internet — underscores their limited capabilities.
In addition, the United States has developed substantial safeguards to prevent the growth of Muslim homegrown terrorism. Although the country’s vast expenditures have occasionally been criticized, the fact is that the 9/11 attacks have spurred significant taxpayer investment in homeland security, in which domestic counterterrorism plays a prominent role, which in 2012 totaled approximately $70 billion. The role of Muslim communities in exposing suspected aspiring militants through unsolicited tips and cooperation with law enforcement, as well as the sometimes controversial use by the FBI and law enforcement of informants, provides a hedge against violence.
Put simply, Americans can be reassured that the terrorism threat posed by Muslims residing in the United States remains small. As horrific as they were, the Boston attacks are not evidence that homegrown terrorism is on the rise.
Risa Brooks is associate professor of political science at Marquette University. She is the author of “Muslim Homegrown Terrorism: How Serious Is the Threat?” which appears in the journal International Security.