Philip Cook is ITT/Sanford Professor of Public Policy and Professor of Economics and Sociology at Duke University. An honorary Fellow in the American Society of Criminology and an elected member of the Institute of Medicine of the National Academy of Sciences, Cook is one of America’s leading experts on crime policy and on efforts to reduce gun violence. Most recently, Cook and his Duke University colleague Kristin A. Goss co-authored the valuable primer: The gun debate: What everyone needs to know.

I caught up with Professor Cook to discuss what might be done to reduce gun violence in the wake of this week’s shootings in Santa Barbara. (Full disclosure: Cook and I are colleagues on a study of Chicago gun violence.)

Harold Pollack: The Santa Barbara perpetrator, Elliot Rodger, exhibited troubling signs before he committed these crimes. His mother had actually alerted mental health authorities, and he was visited by the police. But the police found no specific grounds to detain him or to search his apartment. As always, some important information was overlooked or not shared across different helping or law enforcement systems. In the wake of an atrocity, the warning signs seem much more definitive than they reasonably could have before. Is there anything we might realistically do to identify such perpetrators ahead of time?

Philip Cook: Each case is different. From what we know of Elliott Rodger, it is relevant that he was an adult and that he did not have a criminal record or history of mental-health crises. When the police visited his home, they made what sounds like a reasonable judgment that he was not an immediate threat, despite the scary manifestos that he was posting. Hindsight is 20-20, and now we know that he had become a very dangerous individual. But in the absence of a specific credible threat of violence, it is hard to see what could have been done within existing law.

HP: Rodger legally purchased the guns he used to commit mass homicide. As far as we know, he was not a “prohibited purchaser.” He had never been convicted of a felony or other pertinent crime. He was never involuntarily committed or found to be mentally incompetent. He hadn’t been detected making the kind of specific threats that might have triggered immediate intervention. Despite a troubling history of mental health concerns, this young man remained legally entitled to own a gun. I understand why the threshold must be very high to hospitalize somone against his will. But has the pendulum swung too far regarding whom we trust to purchase lethal weapons?

PC: There is a national debate focused on mental illness and guns. The federal Gun Control Act only disqualifies a portion of those with severe mental illness – people who have been involuntarily committed to a mental hospital, or have been ruled mentally incompetent by a judge (“not guilty by reason of insanity,” for example).

Many experts believe that the federal rule is at once too broad and too narrow. A lifetime disqualification for involuntary commitment may be too broad, because most people who are severely mentally ill are not dangerous to others. It is too narrow, because many of those who are dangerous due to their mental illness are not disqualified by this law.

Among the approaches that make sense for redressing this problem is to bar people from gun ownership who are temporarily confined due to a mental health crisis in which they appear dangerous to self or others. Indeed, California has just such a rule, although most states do not. In California the “5150” confinement is for 72 hours, and can be implemented by an officer or qualified clinician. If their guns are removed during this period, individuals are given the opportunity to reclaim them, assuming that they are not involuntarily committed.

Another approach also makes a good deal of sense, and that is to broaden the list of crimes that will disqualify someone from gun ownership. Currently federal law disqualifies anyone with a felony conviction, but not those who have been convicted of violent acts at the misdemeanor level, no matter how often. The evidence suggests that convicted violent criminals should not be trusted with a gun. The same appears to be true for those with multiple DUIs on their record. While these measures would not focus on mental illness, it is an issue in the near background for DUIs and violence.

HP: The DUI provision also makes sense for other reasons. By some measures two-thirds of incarcerated individuals who’ve been diagnosed with severe mental illness also have accompanying substance use disorders. Individuals with SMI who don’t have these substance use disorders are much less likely to become involved in violence. You are quite familiar with our Crime Lab finding that one-third of murdered young men in Chicago had high blood alcohol content at the time of death….

PC: Right, I remember.

HP: You have closely researched the link between alcohol misuse and crime. Can you provide a bit more information about why a federal alcohol tax increase might reduce violence? What do you have in mind, and what kind of an effect would you reasonably expect from that?

PC: The last time that Congress increased the federal excise tax on alcoholic beverages was 1991. At the time it was a substantial increase – for example, the beer excise was doubled – although it is been pretty much repealed by inflation since then. I recently published an analysis with Christine Durrance indicating that that increase has a measurably large effect on violent crime, as well as highway fatalities and other injury deaths.

The size of the tax effects were much smaller for relatively “dry” states (Utah) than “wet” heavy-drinking states (Wisconsin), just as would be expected. (The importance of drinking as a cause of accidents and violent crime increases with the amount of drinking in the state.) The initial reduction in violent crime as a result of the federal tax increase was 9% in Michigan, the median state when it comes to alcohol consumption.

HP: I also wanted to ask you about Rodger’s age. Like so many perpetrators, he was pretty young. He was only 22 years of age. Would a higher minimum age for legal handgun purchase potentially improve public safety?

PC: The current minimum age for purchasing a handgun from a licensed dealer is 21, but youths as young as 18 can legally purchase handguns from people who are not dealers. The case for making 21 the minimum age across the board starts with the fact that involvement in serious crime tends to peak in late adolescence and early adulthood. It also seems reasonable to compare the gun laws with the alcohol laws – youths are everywhere barred from alcohol purchase till age 21, and is a handgun really less dangerous than a beer?

HP: Mass shootings by disturbed individuals comprise a very small fraction of American gun homicides. Is there a danger that such horrific incidents might be misleading as a guide to preventing more common forms of gun homicide?

PC: Mass shootings galvanize public attention to the problem of gun violence, and serve as horrific reminders that no one is entirely safe from this scourge. Too often, though, the media accounts are focused on the question of what could have been done to prevent the last mass shooting, and provide no perspective on the chronic problems of gun violence – the half million assaults and robberies, the 11,000 gun homicides, and the 20,000 gun suicides that occur each year. Even if there is no easy answer to the question of what could be done about Elliott Rodger, there are a variety of promising actions that would be helpful in reducing gun misuse.

HP: If you could propose one or two policies to reduce gun homicide and that have some prospect of making it through Congress, what would you emphasize?

PC: Tough question. Congress is simply not a promising venue for action against gun violence, not these days. There has been some hopeful talk about a bipartisan deal around mental health and guns, but don’t hold your breath. Even federal action to reduce violence (regardless of weapon type) seems unlikely to be forthcoming, but there is a somewhat better chance there: I would suggest expanded financial support for local police departments through the COPS program, and an increase in the federal alcohol excise tax rates, for starters.

I suspect that the “action” in the near future, as it has been during the last year, will be in the state legislatures.

HP: What would you like to see states do, even in areas that go beyond what Congress is likely or able to do at the federal level?

PC: In the “laboratory of the states,” we can hope to learn from systematic analysis of innovations. For recent examples, almost half the states have adopted Stand Your Ground laws, and two studies by economists found similar conclusions: the effect has been to increase the homicide rate, with no reduction in assault, robbery or rape. An analysis of Missouri’s repeal of their universal background check system in 2007 demonstrated quite convincingly that it resulted in a [14 percent] jump in gun homicides (with no change in non-gun homicides). We are still awaiting an analysis of California’s requirement that pistols be designed to stamp a serial number on the shell casing, so that police investigators can link shootings to particular guns.

The general direction that makes sense to me is adoption of regulations and law enforcement tactics that have the effect of making guns a liability to criminals. Guns should be readily traced to their owners. The police and courts should work together to deter illicit carrying of guns, and crimes committed with guns should be viewed as more serious than similar crimes with knives. Gang members should understand that if any of their members misuse a gun, they will all pay a legal price (as in Boston’s Operation Ceasefire beginning in 1996).

I’m also sold on the potential of smart guns to make gun-owning households safer. The German firm Armatix has developed a gun that uses RFID technology to unlock a gun (similar to the keys for unlocking cars). Only when the gun is near a special wristwatch can it be fired. This is one of many methods for “personalizing” a gun and reducing the chance of an unauthorized use – say, by other household members (young children, teenagers thinking of suicide) or burglars.

HP: More stringent background checks seem to command broad public support, and may have some beneficial impact on gun violence. What does the available research have to say about the potential of these policies to reduce violence?

PC: Over a dozen states have required universal background checks, at least for handgun transactions. In North Carolina, the requirement goes all the way back to 1921. Unfortunately there has not been much research on the effects of these laws. The one exception is the recent study I mentioned by Daniel Webster and his colleagues of the repeal of the universal background check requirement in Missouri. The evidence is compelling that that repeal facilitated criminal access to handguns and increased the homicide rate substantially.

HP: What about the alternative possibility that there is just little we can do? Given the 200+million guns in American society, the political gridlock that surrounds almost every aspect of gun policy, and constitutional constraints imposed by recent judicial interpretations of Second-Amendment law, are we doomed to see high levels of gun violence for the foreseeable future in America?

PC: The belief that nothing can be done to reduce gun violence is widespread and a great impediment to concerted mobilization in this area.

So many reasons to be pessimistic! Let me try to address them one by one:

The Second Amendment: In 2008, the US Supreme Court for the first time found a personal right to guns in the famously obscure Second Amendment. But that decision (Heller v. District of Columbia) makes clear that the new right is not unlimited. Since then there has been a “tsunami” of litigation attacking various firearms regulations, with very little success in the federal courts. It appears that the Constitutional door is open for measures that stop short of an outright ban on possession.

Political gridlock: While there has been gridlock in Congress for the last decade, the states and some localities continue to be active. The big picture is that the NRA, which is not afflicted with pessimism, has been fabulously successful in moving their agenda over the last 3 decades – barring cities from regulating guns, repealing restrictions on carrying guns in public, decriminalizing some kinds of homicide (through the Stand Your Ground laws). There remain some blue states that have bucked the trend, including California and New York, and they include about one-quarter of the US population.

Guns are everywhere: There are enough guns in circulation to provide every adult with one, but of course that’s not the pattern – in fact, only one-quarter of adults own a gun (and they own an average of 4 or 5 each). Furthermore, gun ownership is much more common in some areas than others – just compare New York City with Phoenix. In any event, each new cohort of youths at high risk of violence may have an interest in carrying guns, but most of them do not – less than one-third of street robberies are committed with a gun, for example. In surveys, a high percentage of arrestees report that they would have trouble in obtaining a gun. It is not surprising, then, that several specific regulations have been shown to be effective in reducing gun violence.

We are doomed: Well, maybe, but note that gun homicide rates have been cut in half since 1991 in the U.S. American cities are far safer today than they were a generation ago. That is a reminder that gun violence is the combination of guns and violence. Violence rates of all sorts have come down dramatically, and as a result the gun-violence problem has been reduced. (Unfortunately there has been no progress during this period against suicide.) That does not mean that we’ve “solved” the gun violence problem, only a reminder that where guns are a particular problem, it is when combined with high rates of violence.