Homegrown terrorism actually declining.

• Position: Homeland Security

Concerns of counterterrorism officials about a potential wave of homegrown violent extremism have not materialized over the past two years, a study released by the Triangle Center on Terrorism and Homeland Security documents. The study reports that 20 Muslim-Americans committed, or were arrested for, violent terrorist crimes in 2011, down from 26 in 2010 and 49 in 2009.

Since 9/11,193 Muslim-Americans have been arrested or convicted of violent terrorism offenses, making 2011 about an average year in that department. "Muslim-American terrorism continued to be a miniscule threat to public safety last year. None of America's 14,000 murders in 2011 were due to Islamic extremism," stresses Charles Kurzman, author of the study and professor of sociology at the University of North Carolina, Chapel Hill. "The challenge is for Americans to be vigilant about potential violence while keeping these threats in perspective:

"Those who predicted an inevitable, rapid increase in homegrown violent extremism among Muslim-Americans were wrong," notes David Schanzer, director of the center and professor of public policy at Duke University, Durham, N.C. "While homegrown radicalization is still a problem, the offenders from 2011 were less skilled and less connected with international terrorist organizations than the offenders in the prior two years. Hopefully, the seriousness of this threat will continue to decline in the future."

A total of 462 Muslim-Americans have been arrested for...