Against the backdrop of so much global suffering and conflict or the deadly attack at the Boston Marathon, the handful of ricin letters sent to U.S. political leaders last week seems insignificant, almost narcissistic. Certainly from a national security perspective there is little need for concern; the letters were clearly not the work of professional terrorists. And yet my sense is that officials are a bit too quick to dismiss the letters as simply the work of disturbed amateurs with no broader meaning. We need to ask two questions: Why ricin? Why now?

The ricin letters appear to be the updated and metastasized form of an old American tradition. The United States has long been known for the tendency of its crankier citizens to write letters to public officials. Of course, an equally time-honored tradition is for public officials to ignore letters from citizens. Thus, the new and improved 21st century version of the tradition adds punch by sprinkling the letters with biological agents, one of the most dreaded technologies of our day. Ricin thus serves to help cut through the clutter and get people’s attention.

Further, protest actions only have impact if others can interpret their meaning. Thanks to the deadly anthrax letters, adding biological agents to letters, even poorly made ones, now has a clear meaning. Regardless of what else we know about the people who sent the ricin letters, we know they were angry enough with the government to cause death to innocent people. This in itself represents at least a partial success for the perpetrators, who after all are seeking to draw attention to their grievances. Ricin is thus an easy option for those who want to borrow the language of the anthrax attacks but who lack the skills necessary to create more deadly toxins. Despite the less deadly outcomes, the ricin letters will serve to more firmly establish this tactic in the American protest vernacular. At this point it is easy to predict that we will see more such letters in the future.

Second, we must ask why the ricin letters appeared at this particular time. After all, there have always been people angry with the government. There are several levels at which we can answer this question. At the individual level we can look at the suspects and perpetrators—angry, unhinged people who finally snapped and went “lone wolf.” There is certainly something to this explanation, and yet it helps more with the “who” than the “why now” question. There are always unhinged people among us but they typically don’t send deadly letters through the mail.

At a policy level, we can look at the latest perpetrator’s anger about Mayor Bloomberg and President Obama’s gun control efforts. This explanation makes sense on paper—the gun-control debate has been intense since Sandy Hook and the gun right’s groups have mobilized accordingly, possibly sending one of their less stable members into deadly action. The explanation becomes less satisfying, though, when we think back to other gun control showdowns over the past thirty years, none of which resulted in this kind of behavior.

A more complete explanation requires a broader perspective. Consider the social and political backdrop against which the ricin incidents occurred: Political polarization in Washington is at an all-time high; political leaders routinely belittle and disrespect the President, opposing partisans in Congress, and the government more generally. Public trust in the government has cratered, reaching all-time lows. And over the past generation a growing number of Americans have faced greater economic uncertainty without hearing any convincing answers from their government about when or how things will get better.

Thus, a plausible case can be made that increasing social, economic and political pressures have combined to push some people further out on the spectrum of violence than they would have gone twenty or thirty years ago. When combined with the new, technology-fueled language of protest these trends in American society and politics make the ricin letters far less surprising in 2013 than they would have been in 1985.

A. Trevor Thrall is an associate professor of government and politics at George Mason University and director of the Biodefense Program. He is the coeditor of American Foreign Policy and the Politics of Fear: Threat Inflation since 9/11 and coeditor of Why Did the United States Invade Iraq?