Editor's note: James Alan Fox is the Lipman Family Professor of Criminology, Law and Public Policy at Northeastern University in Boston and co-author of "Extreme Killing: Understanding Serial and Mass Murder."
(CNN) -- Outrageously tragic crimes -- like the mass shooting in Tucson, Arizona, on Saturday that claimed the lives of six people and caused serious injuries to many more -- typically set off a round of finger-pointing.
Once the emotional shock has passed, a multitude of critics and speculators seize the opportunity to place blame, even beyond just the shooter.
Given that it was a congresswoman, Gabrielle Giffords, who appears to have been the prime target of the gunman, many observers have emphasized the role of acerbic political discourse, commonplace today in the electronic media and cyberspace. According to this view, the assailant was inspired and encouraged by strident and hateful words often thrown about to characterize government officials of either side of the political spectrum.
Others have focused specifically on the suspect's MySpace page and YouTube videos as a window into his thinking and mindset. In the aftermath of almost any major murderous incident, survivors tend to question why certain warning signs were ignored.
The accused assailant in Saturday's massacre is, by all accounts, fairly typical of mass murderers -- angry, a poor achiever, socially isolated, and tending to blame others for his shortcomings and for societal ills. If anything, however, these warning signs are yellow flags that only turn red after the blood has spilled. Of course, these "telltale signs" only come into focus with 20/20 hindsight.
The challenge is a matter of finding needles in haystacks. There is a very large haystack of people who closely match the profile, but very few needles who will in fact commit murder, let alone mass murder.
In the wake of mass shootings like Saturday's episode, gun control advocates question how an individual with a history of trouble-making and an obviously unstable pattern of behavior at school and in his neighborhood was able to acquire his own weapon of mass destruction, just by walking into a local sports shop and walking out with a high-capacity, semi-automatic Glock.
Although similar events have occurred in countries having far more restrictive gun laws, momentum builds for making it more difficult for madmen and hatemongers to get revenge with a gun.
At the same time, many gun owners argue that concealed carry laws permit legally armed bystanders to stop a gunman in his tracks. Of course, Arizona has one of the most permissive concealed carry rules, yet as bystanders subdued the attacker on Saturday, none of them used a gun.
The truth pertaining to all these dilemmas is that mass murder is rare, unpredictable and largely unpreventable. Over the past three decades, on average, about 20 mass shootings -- with at least four slain victims -- have occurred annually in the United States, claiming nearly 100 lives each year.
Without minimizing the pain and suffering of these victims and their families, the risk of this type of crime is significantly less than a wide array of other catastrophes that we confront every day.
Hopefully, Saturday's tragic shooting will promote some changes for the better. But even though upgrading the level of political discourse, enhancing the scope and quality of mental health services, and changing gun laws (whether stricter or more permissive) may have some value in a general sense, these steps will likely not make a shred of difference in reducing the incidence of mass murder.
Mass killers, though often delusional, are deliberate and determined. They seek revenge against specific individuals, or against society as a whole, in large part regardless of whatever social policies we put in place.
Short of rounding up all the guns and all of those who spew angry epithets or appear psychologically unstable, senseless episodes like the Tucson shooting will continue to occur. Mass murder is but one of the difficult and unfortunate prices that we pay for our freedoms.
The opinions expressed in this commentary are solely those of James Alan Fox