Editor's Note: (Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of "United States of Jihad: Investigating America's Homegrown Terrorists.")
(CNN) When I was researching a book about Americans becoming violent jihadists, again and again I was struck by how often they were men who were going nowhere fast in life and who turned to violent jihadist ideology as a way of giving their lives greater meaning. They were often zeros trying to be heroes in their own story.
The terrorist incidents of the past week in the United States show that this can also be the case for alleged right-wing terrorists such as Cesar Sayoc, who is accused of mailing crude bombs to prominent Democrats and others, and Robert Bowers, who is accused of killing 11 at a synagogue in Pittsburgh.
Both Sayoc and Bowers display some of the same characteristics as American jihadist terrorists: losers who attached themselves to extremist right-wing ideologies that gave meaning to their otherwise dead-end lives.
Consider some well-known American jihadist terrorists. Tamerlan Tsarnaev and his younger brother Dzhokhar blew up bombs killing three spectators at the Boston Marathon in 2013. At the time of the bombings, Tamerlan was unemployed and unemployable. His dreams of being an Olympic-level boxer had long faded and the heroic figure that his family had once looked up to was now sitting on his couch at home, wholly dependent on his wife, who was working 80 hours a week. By becoming a jihadist, Tamerlan was in his own mind once again the heroic figure that he fervently believed himself to be.
Consider also Nidal Hasan, who killed 13 at the Fort Hood army base in Texas in 2009. Hasan was about to turn forty, and he was unmarried and almost entirely friendless. He was a mediocre army officer who had recently been ordered to go to Afghanistan, which he was very worried about. On his business cards, Hasan had printed the words "SOA," which was short for "Soldier of Allah." Hasan secretly saw himself as a holy warrior, and the massacre at Fort Hood was his twisted way of becoming that warrior he dreamed of being.
American forensic psychologist Reid Meloy, together with Jessica Yakeley, published a 2014 study of terrorists such as Hasan, people who were not part of a formal terrorist organization. They found that they started with a "grievance" that was often "an event or series of events that involve loss and often humiliation of the subject. ... Such intense grievances require that individuals take no personal responsibility for their failures in life ... they are 'injustice collectors.'"
Meloy, who has consulted with the FBI, explains that what often follows the grievance is "moral outrage," which is embedded "in an historical, religious or political cause or event." Grievance and moral outrage are then "framed by an ideology," but the ideology is secondary; it functions as rationale for the terrorist to carry out the violent act he is planning. Meloy explains, "This framing is absolutist and simplistic, providing a clarity that both rationalizes behavior and masks other, more personal grievances."
This seems like an almost perfect description of Cesar Sayoc, 56, of Aventura, Florida who had led an itinerant life as a sometime male dancer, occasional DJ at a strip club, and pizza delivery guy. At the time of his arrest, Sayoc was living out of a van plastered with images of President Donald Trump and of some of Trump's critics with targets over their faces. Sayoc also posted virulently anti-Muslim messages on the Internet.
Sayoc was arrested Friday by the FBI after he had allegedly sent 15 crude bombs to prominent Democrats, former officials and CNN. The bombs didn't explode.
Robert Bowers, the man accused of gunning down 11 at the Pittsburgh synagogue, fits the same profile as Sayoc. According to the New York Times, Bowers lived in a "shabby one-bedroom" apartment and was "an isolated, awkward man who lived alone and struggled with basic human interactions."
Bowers had posted multiple anti-Semitic and anti-immigrant posts on Gab, a social media network, before he carried out the massacre at the synagogue. Bowers frequently posted conspiracy theories about the migrant march now wending its way through Mexico to the United States, which is a major preoccupation of Trump supporters.
For his assault, Bowers used the weapon of choice for mass shooters in the United States: the AR-15, a semi-automatic rifle that is a perfect weapon to kill lots of people.
What to do about these lone terrorists who are unconnected to formal jihadist organizations or to right-wing extremist groups? The obvious start would be tightening gun laws around semi-automatic weapons that are designed to kill other human beings. My in-laws in Louisiana do not go deer hunting with AR-15s.
But good luck with that, as the NRA has killed the most modest gun control measures, even in the wake of the 2016 Pulse nightclub massacre in Orlando, in which 49 were killed by another loser-turned-jihadist, Omar Mateen. Mateen had legally purchased semi-automatic weapons, despite the fact that he had been interviewed twice by the FBI because of his jihadist sympathies.
So, we will continue to live in country where massacres by American jihadist terrorists and right-wing extremists, enabled by the laxest gun laws in the West, will be a regular feature of American life. Pity that the right to life of their many victims is outweighed by the Second Amendment absolutists at the NRA.
The truth is that zeros wanting to be heroes, motivated by a number of toxic ideologies and armed with semi-automatic weapons, will likely continue to massacre Americans at frequent intervals for the foreseeable future.