In just over seven weeks, voters will decide the fate of the three 2012 state marijuana initiatives to legalize possession and use of the plant for adults in Colorado, Oregon, and Washington State. As the polling data available for these measures continue to warrant optimism among those in favor of ending marijuana prohibition, it is no surprise that nine former heads of the Drug Enforcement Agency recently wrote a letter to Attorney General Eric Holder encouraging him to take a public stance against the legalization initiatives.
The letter itself isn’t entirely notable for any detailed policy advocacy. It simply says silence on the issue is tantamount to acceptance while also making the rudimentary point that state ratification is irrelevant, as federal law preempts state law and marijuana remains criminalized at the federal level.
However, one small aspect of the letter warrants attention, and that happens to be the language describing these initiatives as “dangerous.” The letter did not go on to say why these ballot measures are dangerous or what the danger of a legally regulated market for marijuana encompasses. It did not explicitly outline what dangers are posed by these legalization initiatives, but these former DEA chiefs are likely referring to public safety and crime.
It is a common argument among the most ardent proponents of drug prohibition that liberalizing marijuana laws will lead to increases in crime. Drugs and crime go hand in hand together, they argue, so by making marijuana legal and more readily available, increases in violent and property crime will naturally follow.
Similar contentions have been made regarding states that have already passed medical marijuana laws. The perception is that making marijuana more available through brick and mortar medical dispensaries actually creates the conditions for crime to thrive. This argument can be equally applied to the three state legalization initiatives that would allow for brick and mortar selling of recreational marijuana.
This was even one of the reasons specifically cited by Arizona Governor Jan Brewer when she opposed Arizona’s medical marijuana law, claiming dispensaries would essentially serve as a magnet for criminal activity. Moreover, law enforcement officials in Colorado also contend that crime associated with medical marijuana dispensaries is on the rise, though there is no concrete evidence to back up the contention.
While prohibitionists are concerned that liberalizing marijuana policy, even via careful regulation of medical marijuana, will result in an increase in crime and threats to public safety, the evidence of empirical studies suggests otherwise. In fact, the only methodologically rigorous research to tackle the association between crime and medical marijuana dispensaries found no correlation between marijuana dispensaries and crime. 
In a paper recently published in the Journal of Studies on Alcohol and Drugs, UCLA scholars Nancy J. Kepple and Bridget Freisthler discovered that “density of medical marijuana dispensaries was not associated with violent or property crime rates” in Sacramento, California.
The paper used the routine activity theory to attempt to understand how the existence of medical marijuana dispensaries may impact crime. In criminology, routine activity theory posits that crime results from the convergence of three conditions: (1) a motivated offender; (2) a suitable target (based on value, access, visibility); and (3) the lack of a capable guardian (such as inadequate security or the absence of management or agents to watch and monitor behavior).
Kepple and Freisthler go on to explain how medical marijuana dispensaries and their surrounding areas may be suitable targets for crime (citations removed):
“Applying routine activity theory to medical marijuana dispensaries suggests that dispensaries may uniquely contribute to crime even when other contextual factors associated with crime have been controlled. They have on-site stock and sales of marijuana and are a predominantly cash-based business. The centralized location of the goods—marijuana and cash— within the dispensaries makes the location a suitable target for a potential offender who might be motivated to seek out ways to obtain the desirable goods, particularly where security appears to be absent.
Based on the conditions described above, dispensaries can be at risk for property crimes, such as burglary. Employees of the dispensaries can be at risk for violent crimes, such as robbery or assault, because they are gatekeepers to both the marijuana products and the cash at the site. Estimates from the western United States and other countries show that users of medical cannabis are primarily male (i.e., two thirds to three fourths of all users) and White, with a wide range of ages (i.e., late teen years to old age; median age between 30 and 50). The typical clientele for dispensaries (i.e., older White men) are not associated with being at risk for perpetrating crime. However, they are at risk for being targets of violent crimes, such as robbery, because they are likely carrying cash on entry and some physical amount of marijuana product on exit. In addition, medical marijuana dispensaries have a diverse clientele, with some who are older, frail, and/or diagnosed with chronic, debilitating conditions. These more vulnerable clients may appear to be easier targets for a motivated offender and are at higher risk for victimization.”
The authors then “used an ecological, cross-sectional design to explore the spatial relationship between the density of medical marijuana dispensaries and crime rates in the City of Sacramento.” In sum, the study finds that “cross-sectional results suggest that dispensaries are not associated with crime rates.”
While commercial zoning, one-person housing units, and the unemployment rate were all positively associated with both violent and property crime rates, “no cross-sectional associations were observed between the density of medical marijuana dispensaries and violent or property crime rates, controlling for ecological variables traditionally associated with routine activity theory.”
From these findings, the authors draw two possible conclusions:
“First, the density of medical marijuana dispensaries may not be associated with neighborhood-level crime rates. For example, dispensaries may be associated with crime but no more than any other facility in a commercially zoned area with conditions that facilitate crime. Alternatively, the relationship between density of medical marijuana dispensaries and crime rates is likely more complex than measured here. The study did not measure on-site security or guardianship at the dispensaries. If medical marijuana dispensaries have strong guardianship, such as security and monitoring systems, routine activity theory would suggest that the three necessary conditions for crime are not met. Place-specific guardianship would decrease the accessibility and increase the risk of being caught, decreasing the suitability of a target.”
While the study cautions, “no conclusions can be made about causation,” at the “aggregate level, dispensaries in Sacramento are not associated with crime cross-sectionally,” the authors also discuss other possible, yet unmeasured factors, such as sample size, locations of illicit drug markets, marijuana dispensary locations, and alcohol stores that may be at play. And they further note that greater exploration of these conditions, as well as others, including dispensary owner decision-making, larger cities, and dispensary vulnerability or resistance to crime is essential to build on this initial research.
As the authors’ findings suggest, their research stands in stark contrast to the arguments of prohibition advocates against legalization initiatives. As we move closer and closer to election day, however, and the real possibility that at least one of these legalization initiatives will pass, we should expect to hear more and more from opponents of marijuana legalization.
Yet while an official of the White House Office of National Drug Control Policy recently claimed to embrace a scientific approach to drug policy and argued that legalization advocates are blinded by their ideological zeal, the science, in this instance, contradicts the main argument of prohibition advocates, showing that there is no correlation between the increased existence of brick and mortar marijuana dispensaries and violent crime or property crime.
 A study predating this one finding crime increasing after medical marijuana dispensaries closed was pulled for alleged methodological reasons.