Another U.S. shooting spree has left bullet-riddled bodies in its wake, and refocused attention on violent, right-wing extremists. Frazier Glenn Miller, a former leader of a wing of the Ku Klux Klan, is accused of killing three people outside two Jewish community centers outside Kansas City, Kan. As he was hauled away in a police car, he shouted “Heil Hitler!” Unlike Islamic groups that U.S. agencies spend tens of billions of dollars targeting, domestic white supremacist groups enjoy relative freedom to spew their hatred and promote racist ideology. Too often, their murderous rampages are viewed as acts of deranged “lone wolf” attackers. These seemingly fringe groups are actually well-organized, interconnected and are enjoying renewed popularity.In April 2009, the U.S. Department of Homeland Security (DHS) released a study on right-wing extremists in the United States. The 10-page report included findings like “The economic downturn and the election of the first African American president present unique drivers for rightwing radicalization and recruitment.” It controversially suggested military veterans returning from Iraq and Afghanistan could potentially be recruited to join hate groups. The report provoked a firestorm of criticism, especially from veterans groups. The Obama administration was just months old, and newly appointed Homeland Security Secretary Janet Napolitano withdrew the report, apologizing for it during a congressional budget hearing.Mark Potok is a senior fellow at the Southern Poverty Law Center, which has been tracking right-wing hate groups and Frazier Glenn Miller for years. Potok said, about that report, “a real problem with the Department of Homeland Security ... ever since a particular report on the right wing was leaked to the press in April of 2009, DHS has sort of cowered. They essentially gutted their non-Islamic domestic terrorism unit.”The SPLC was co-founded in 1971 by civil-rights lawyer Morris Dees. It began suing white supremacist groups in the 1980s, representing clients that the groups threatened, beat and harassed. Potok described Frazier Glenn Miller as “one of the best-known white supremacist activists in the country for a very long time ... active for more than 40 years in the movement. He joined, as a very young teenager, things like the National States’ Rights Party, a descendent of the American Nazi Party.” Miller formed his own wing of the Klan, which marched publicly in military fatigues. He had dealings with another supremacist group, The Order, that gave him $200,000 from the more than $4 million stolen through bank robberies and armored-car holdups.After being sued by the SPLC, Frazier Glenn Miller agreed to a settlement in one case, but violated the terms of the agreement and was found guilty of criminal contempt. While out on bond, he disappeared, issuing a crudely typed “Declaration of War,” specifically targeting Morris Dees for murder. He was eventually arrested. Potok told me, “He was initially charged with conspiracy, very serious charges, in 1987 that could have sent him to prison for 20 or 30 years. But he cut a deal with the federal government and agreed to testify ... against his comrades. That wound up meaning a mere five-year sentence for him, and he served only three years.” Miller cooperated with federal prosecutors, testifying against 13 white supremacist leaders. He was released from prison and was assisted, it is believed, by the Federal Witness Protection Program as he relocated to Nebraska and changed his last name to “Cross.” Frazier Glenn Miller, also known as Frazier Glenn Cross, lost credibility with other white supremacists and faded into relative obscurity. He occasionally ran for office in Missouri, after running virulently racist campaign ads on radio. Then he went on his murderous rampage this week. “Perhaps if he had been in prison all those years rather than a witness in this trial,” Potok reflected, “we wouldn’t have experienced what we saw in Kansas City the other day.”Potok and the SPLC track the recent rise of right-wing hate groups. When I asked him about the FBI’s focus on animal rights and environmental groups, he replied, “The idea that eco-terrorists, so-called, are the major domestic terror threat, which was in fact said to Congress a couple of times by FBI leaders during the Bush years, I think is just patently ludicrous ... no one has been killed by anyone in the radical animal-rights movement or the radical environmentalist movement.” The SPLC will soon release a report that links registered members of two prominent white supremacist online forums to more than 100 murders in the United States—in just the past five years.While law-abiding Muslims are forced to hide in their homes, and animal-rights activists are labeled as terrorists for undercover filming of abusive treatment at factory farms, right-wing hate groups are free to organize, parade, arm themselves to the hilt and murder with chilling regularity. It’s time for our society to confront this very real threat.Denis Moynihan contributed research to this column.