In the last four weeks alone, six mass shootings have killed 47 people in the United States.

Perversely, until the last three massacres took place within a single twenty-four period, the very frequency of what we might call “rage murders” rendered the phenomenon largely invisible, since an isolated shooting no longer seemed exceptional enough held public attention for any length of time.

Australian discussions of such atrocities invariably focus on gun laws, since the centrality of firearms to US culture seems bizarre to most of us. Yet though guns obviously contribute to the problem, they don’t provide, in and of themselves, an explanation as to why so many Americans go berserk. Firearms have been readily available in the United States for many decades but mass shootings are relatively new. Besides, while automatic weapons make anyone more lethal, they don’t in and of themselves generate the desire to shoot.

A few years ago, different explanations abounded. After the 1999 Columbine massacre – and the other school shootings that followed it in Red Lake, an Amish school in Pennsylvania and elsewhere throughout the country — the focus was very much on alienated teenagers. High school killers, we were told, were obsessed with violent video games, horror movies and death metal, a toxic media stew that prepped them for violence.

It’s hard, though, to blame Grand Theft Auto or Marilyn Manson lyrics for the Binghamton killings, where the shooter was no teenaged goth but a 41-year old Vietnamese immigrant, apparently frustrated about losing his job and the mockery he’d received over his poor English.

In that respect, these recent massacres seem closer to the initial outbreak of mass killings in the early eighties. Back then, a series of episodes within the US postal service briefly brought the expression “going postal” into the American vernacular — though, with rage murders occurring in every occupation, it’s since fallen into disuse. In his book of that name, Mark Ames suggests that these crimes too get psychologised away.

On the one hand, designating the killer as a “madman” seems almost tautological — anyone who would commit such a vile act is, almost by definition, unbalanced. On the other, a diagnosis of insanity glosses over the uncomfortable fact that until their rampage, many perpetrators seemed utterly normal. Thus, Ames argues, instead of building a profile of the rage killer, we need to analyse the environment in which such crimes take place.

He points out that, chronologically, the proliferation of rage murders coincided with the Reagan revolution, which normalized casualisation, temping and long hours within previously comfortable white collar industries, and perpetrated a toxic workplace culture of Hobbesian individualism, exemplified by celebrity CEO’s like General Electric’s Jack Welch, who famously boasted of the “unlimited juice” he could squeeze from his workers.

The first killings amongst postal workers, for instance, took place against the backdrop of a long campaign to deregulate and semi-privatise the mail service. Employees steadily lost their job security and entitlements and found themselves working ever harder in far more stressful circumstances. From a source of pride, their work became a locus of anxiety, in workplaces suddenly rife with bullying and petty infighting.

Ames argues that, though the media reported on the postal killers as motiveless berserkers, many of them did have specific grievances: like Samson in the temple, they saw their shooting spree as a despairing act of defiance, bringing down the workplace and everyone in it. Remarkably, Ames uncovered numerous employees who said that, while the crimes were abhorrent, they still sympathized with the men who’d “gone postal” in their workplaces. Michael Campbell, for instance, was shot six times by a rage killer in 1989 but afterwards said that the company was so dysfunctional that “[E]verybody understood where he was coming from”.

According to Ames, Reaganism’s dog-eat-dog mentality also trickled down into the US school system. Adults tend to romanticize their teenage years but many students experience school as isolating and stressful, rife with cliques and bullying about which teachers seem indifferent. Again, where the media tried to explain away Columbine killers Dylan Klebold and Eric Harris as motiveless, a surprising number of young people felt differently. As one former student said, “Columbine was absolutely primed for it, because of the bullying and hate that were so prevalent in our school.’”

It’s scarcely controversial to suggest that the recent uptick in rage crimes in the US owes something to the recession. Job losses, foreclosures — these things make people insecure and angry. Why, though, in America, does that anger manifest in a hail of bullets?

Here’s one explanation. The postal service, where these massacres began, was also the site of a major Reagan-era union busting campaign. Over the last decades, the American union movement has been systematically destroyed, removing from the horizons of most workers a traditional response to workplace stresses. Thus today, where in Europe, the financial crisis has spurred a strike wave, in the US, most employees have to cope on their own. Many cannot, and rage killings take place as a blind and despairing attack on anything and everything.

But there’s another factor. The void once filled by the union hall and the picket line has been increasingly replaced by a pernicious right-wing populism in which an apocalyptic confrontation with (hazily defined) enemies plays a central role. Here’s a friend of Richard Poplawski, explaining the mentality of the 23-year-old who recently ambushed three police officers in Pittsburgh:

He just believed in his right to bear arms; he believed that hard economic times were, you know, gonna put forth a, you know, gun bans. That sort of thing … he uh, he basically believed in what our forefathers had put before us and thought that it was being distorted by the, you know, Zionist control of the government, and he didn’t believe in that.

These are standard tropes of the populist Right, and they’re increasingly getting a hearing in the mainstream. Fox’s Bill O’Reilly, for instance, says Obama’s selling Americans out to a “One World Government”; Sean Hannity says that “the black helicopter crowd” who predicted a UN takeover of the US were right; Glen Beck not only tells his millions of viewers that Obama wants their guns, he also warns them of a coming civil war.

Most rage murderers aren’t as ideological as Poplawski — the grievances of the Binghamton killer seem to have been much more personal. But the violent rhetoric of right-wing populism fosters a militaristic culture, in which armed violence seems attractive, almost noble – an exhilarating alternative to the banality of day-to-day life. To men (and it is mostly men) struggling to keep a poorly-paid and demeaning job, the populist rhetoric facing down one’s tormentors in a heroic last stand can seem appealing, a way of becoming something more than a replaceable cog in an impersonal machine. In that context, the senseless violence of a gun rampage might seem like a way of producing a few moments that actually count.

In short, there’s more to these massacres than America’s lax gun laws. Will there be more of them? One suspects that we’re only at the beginning.