Editor's note: Peter Bergen is CNN's national security analyst, a director at the New America Foundation and the author of "Manhunt: The Ten-Year Search for bin Laden -- From 9/11 to Abbottabad." David Sterman is a research assistant at the New America Foundation. This is an updated version of an article originally published in April.
(CNN) -- On Sunday, Jerad and Amanda Miller, a married couple, allegedly killed two police officers in an ambush at a Las Vegas pizza restaurant and then murdered another person in an adjacent Walmart. During the attack, the couple reportedly stated that their attack was part of a "revolution," according to Second Assistant Sheriff Kevin McMahill.
The Millers appear to have been motivated by extreme far-right views. The couple left a flag at the scene of the crime with the words "Don't Tread on Me," a Revolutionary War symbol used by some anti-government extremists.
They also left a swastika at the scene, though McMahill cautioned to reporters, "We don't necessary believe that they are white supremacists or associated with the Nazi movement. We believe that they equate government and law enforcement ...with Nazis."
McMahill added an assessment of the Millers' ideological roots saying, "There is no doubt that the suspects have some apparent ideology that's along the lines of militia and white supremacists."
McMahill also confirmed that Jerad Miller had written on his Facebook page that he had been ejected from the Bundy Ranch, the Nevada site where armed ranchers as well some with anti-government militia ties held off federal officials at gunpoint in April. However, McMahill was not able to confirm Miller's actual presence at the ranch. (Cliven Bundy's son Ammon said that "state militia members" told him the Millers had been at the ranch, but were asked by a militia member to leave because of "their radical beliefs.")
The attack in Vegas is far from the only incident of violence by the American far right. According to data collected by the New America Foundation, right-wing extremists have killed 37 people in 16 violent incidents, in the United States since the 9/11 attacks. That number is more than the 21 people killed by militants motivated by al-Qaeda's ideology in the United States in the post-9/11 era.
Although a variety of left wing militants and environmental extremists have carried out violent attacks for political reasons against property and individuals since 9/11, none have been linked to a lethal attack.
As we pointed out in this space less than two months ago, a man shot and killed a 14-year-old boy and his grandfather at the Jewish Community Center of Greater Kansas City and then drove to a nearby Jewish retirement community where he shot and killed a third person. Police arrested a suspect, Frazier Glenn Cross, who shouted "Heil Hitler" after he was taken into custody.
Cross, who also goes by Frazier Glenn Miller, is a well-known right-wing extremist who founded the Carolina Knights of the Ku Klux Klan and the White Patriot Party, according to the Southern Poverty Law Center.
A similar attack to the one that Frazier Glenn Cross is accused of in Kansas occurred in August 2012 when Wade Michael Page killed six people in a shooting at a Sikh temple in Wisconsin. Page was a member of a white supremacist band and associated with the Hammerskins, a white supremacist group. Page committed suicide during the attack.
Page is not, of course, the only right-wing extremist to have used lethal violence to achieve political ends. In 2009, for instance, Shawna Forde, Albert Gaxiola, and Jason Bush raided a house in Arizona, killing Raul Flores and his daughter Brisenia. The three attackers sought to use the burglary to finance their anti-immigration vigilante group, Minutemen American Defense. Forde and Bush were convicted and sentenced to death. Gaxiola was sentenced to life in prison.
Also in 2009, Scott Roeder murdered Dr. George Tiller, who ran an abortion clinic in Wichita, Kansas. In 2010 Roeder was convicted of first-degree murder. According to the Southern Poverty Law Center, Roeder not only had ties to the extreme anti-abortion movement, but he also had been pulled over while driving with a fake license plate bearing the markings of the Sovereign Citizens, a movement of individuals who deny that the government has authority over them.
Of course, the deadliest terrorist attack on American soil prior to 9/11 was the Oklahoma City bombing, which was masterminded by Timothy McVeigh, a man with deep ties to far-right militant circles. McVeigh killed 168 people when he bombed the Alfred P. Murrah federal building on April 19, 1995.
Despite the history of deadly violence by individuals motivated by political ideologies other than that of al Qaeda, it is jihadist violence that continues to dominate the news and the attention of policy makers. Some of this is quite understandable. After all, on 9/11 al Qaeda's 19 terrorists killed almost 3,000 people in the space of a morning. Since then al Qaeda's branch in Yemen tried to bring down -- with a bomb secreted on a passenger -- an American commercial jet flying over Detroit on Christmas Day 2009 and al Qaeda's branch in Pakistan tried to launch bombings on the New York subway system a few months earlier. Luckily those plots didn't succeed, but certainly if they had, the death toll would have been on a large scale.
Yet the disparity in media coverage can have serious consequences. McMahill told reporters that he had heard reports that the Millers had spoken to a neighbor about their plans adding "You know we have the 'see something, say something' campaign," and urged that, "We need to hear about those times when individuals or groups of individuals are talking about going out and committing acts of violence -- whether it's against the police or anybody else in our community."
Indeed, in a report on countering radicalization in Muslim communities, the Muslim Public Affairs Council emphasized the need to inform law enforcement when an individual is ejected from a community for being extreme.
Countering violent extremism cannot simply be a demand placed on Muslim communities to prevent jihadist violence. In the decade since 9/11 right-wing extremists have demonstrated their ability to be just as deadly as their homegrown jihadist counterparts.
Moreover, killings like the ones of the two police officers in Las Vegas on Sunday demonstrate the need to move beyond the view that the only threat of terrorism or extremist violence comes from radicalized Muslims.
A promising development to that end is that U.S. Attorney General Eric Holder announced last week that he is reconstituting a Justice Department task force on domestic terrorism, focused on anti-government plots and racial violence. The task force was originally launched after the 1995 Oklahoma City bombing.