Clements was the latest victim of increasingly active violent right-wing extremists. While American politicians and the U.S. public continue to focus on the threat from jihadist extremists, there seems to be too little awareness that this domestic form of political violence is a growing problem at home.

From 2002 to 2007, only nine right-wing extremists were indicted for their roles in politically motivated murders and other types of ideologically motivated violent assaults. But between 2008 and 2012, the number mushroomed to 53, according to data collected by the New America Foundation. (Click on chart on the left for the data.)

Fifteen right-wing extremists were indicted in 2012 — including six who were involved in a militia in Georgia that accumulated weapons, plotted attacks on the government and murdered a young U.S. Army soldier and his 17-year-old girlfriend, who they suspected were planning to rat out the group to authorities. Seven claimed membership in the anti-government Sovereign Citizens movement and allegedly murdered two policemen in Louisiana. And two had gone on a murderous rampage the previous year, killing four people before they were arrested in California, where they told police they were on their “way to Sacramento to kill more Jews.”

More: Opinion: Growing Threat of Extreme Right-Wing Violence