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.