In the 14 years since Al Qaeda carried out attacks on New York and the Pentagon, extremists have regularly executed smaller lethal assaults in the United States, explaining their motives in online manifestoes or social media rants.
But the breakdown of extremist ideologies behind those attacks may come as a surprise. Since Sept. 11, 2001, nearly twice as many people have been killed by white supremacists, antigovernment fanatics and other non-Muslim extremists than by radical Muslims: 48 have been killed by extremists who are not Muslim, including the recent mass killing in Charleston, S.C., compared with 26 by self-proclaimed jihadists, according to a count by New America, a Washington research center.
The slaying of nine African-Americans in a Charleston church last week, with an avowed white supremacist charged with their murders, was a particularly savage case.
But it is only the latest in a string of lethal attacks by people espousing racial hatred, hostility to government and theories such as those of the “sovereign citizen” movement, which denies the legitimacy of most statutory law. The assaults have taken the lives of police officers, members of racial or religious minorities and random civilians.
Non-Muslim extremists have carried out 19 such attacks since Sept. 11, according to the latest count, compiled by David Sterman, a New America program associate, and overseen by Peter Bergen, a terrorism expert. By comparison, seven lethal attacks by Islamic militants have taken place in the same period.
If such numbers are new to the public, they are familiar to police officers. A survey to be published this week asked 382 police and sheriff’s departments nationwide to rank the three biggest threats from violent extremism in their jurisdiction. About 74 percent listed antigovernment violence, while 39 percent listed “Al Qaeda-inspired” violence, according to the researchers, Charles Kurzman of the University of North Carolina and David Schanzer of Duke University.