Editor's note: John P. Avlon is a senior political columnist for The Daily Beast and author of the new book "Wingnuts: How the Lunatic Fringe is Hijacking America."
New York (CNN) -- At least 10 death threats have been leveled against members of Congress since the health care vote. Windows at four district offices or county party headquarters have been shattered with bricks.
A gas line was severed at the home of the brother of one Democratic congressman from Virginia, and a man was arrested for making death threats against Republican Minority Whip Eric Cantor and his family.
And Monday, nine members of a Michigan-based anti-government militia group called the Hutaree were charged with conspiring to kill law enforcement officers.
These incidents may be following the drumbeat of incitement offered by a new breed of anti-government paramilitary organizations that have proliferated during the Obama presidency. Their members are self-styled patriots, armed and ready for a new American Revolution. They warn of martial law, seizure of guns, and imposition of global government, complete with forced internment camps and mass executions.
When love of country is mixed with fear of the government and hate for the president, that's when you become a Hatriot. We've confronted these forces before as a country. The record shows that the Hatriots are not part of a benign movement of patriots, but a dangerous strain of extremism with both a rap sheet and a body count.
In 2009, the Southern Poverty Law Center tracked a 300 percent increase in the number of militia groups operating in the United States -- from 42 to 127 such groups at the year's end.
One of these, the 3 Percenters, was co-founded by Mike Vanderboegh, who explicitly encouraged supporters to throw bricks as part of a post-health care vote protest: "If we break the windows of hundreds, thousands, of Democrat party headquarters across this country," he wrote on his blog, "we might just wake up enough of them to make defending ourselves at the muzzle of a rifle unnecessary." As a quote on the homepage of Vanderboegh's Web site warns, "All politics in this country now is just dress rehearsal for civil war."
Another new Hatriot group is the Oath Keepers, who claim to have some 3,000 dues-paying members, including current and former law enforcement officers, members of the military, and others who meet to reaffirm their oath to defend the Constitution against all enemies, foreign and domestic. "The whole point of the Oath Keepers is to stop a dictatorship from ever happening here," its founder, Stewart Rhodes, told the Las Vegas Review-Journal.
Rhodes, a graduate of Yale Law School, former army paratrooper and former staff member for Congressman Ron Paul, says, "My focus is on the guys with the guns, because they can't do it without them. ... We say if the American people decide it's time for a revolution, we'll fight with you." Rhodes says his group is not a militia.
America has seen militarized radical groups in the past, playing off the same fears. Survivalist groups like the Minutemen began developing a "patriotic resistance" movement patterned after colonial militias in the early 1960s, doing wilderness military drills and hoarding weapons and ammunition in advance of what they said was a plan to "confiscate all private fire-arms by the end of 1965." This prompted President Kennedy to warn of "armed bands of civilian guerillas that are more likely to supply local vigilantes than national vigilance."
Radical and violent anti-government groups do not, of course, just reside on the far right. During the late 1960s, there were more than 1,000 shootings, arsons and bombings from left-wing radical groups. But the recession of the late 1970s saw the rise of Posse Comitatus groups which claimed there was a "criminal conspiracy to obstruct justice, disfranchise citizens and liquidate the Constitutional Republic of these United States."
By the 1990s, America experienced the rise of the anti-government patriot militia movement, paramilitary groups fueled by anger at the Bill Clinton-led federal government after deaths at Ruby Ridge, Idaho, and Waco, Texas.
The destruction of the Murrah Federal Building in Oklahoma City, Oklahoma, was the culmination of years of escalation. In total, there were 845 acts of domestic terrorism from far-right and white supremacist groups between 1954 and 2004, including shootings, bombing and arson.
Today's Hatriots are potentially even more dangerous because of their ability to recruit and radicalize people via the Internet. They have proliferated in an environment where fear and hate are used to pump up hyperpartisanship -- including elected officials raising the specter of secession and talk radio hosts blurring the line between losing an election and living under tyranny.
There is an understandable impulse to dismiss the danger of the lone wingnut whose posts dot Hatriot Web sites. But in the last year, we have seen a half-dozen murders committed by unhinged individuals who drank deeply from Hatriot and anti-government conspiracy theory sites, including those implicated in the deaths of three Pittsburgh, Pennsylvania, police officers and two Florida sheriff's deputies.
History shows us that it is most often the unhinged lone gunman who takes the hate as a call to misguided heroism -- the small but decisive step from being ready to die for a cause to being willing to kill for it.
The opinions expressed in this commentary are solely those of John P. Avlon.