It's 4/20, Aka Cannabis Day:Colorado, Pot, and Guns

image, azmarijuana.com

is also the anniversary of the Columbine massacre in Colorado in 1999.  Colorado has legalized marijuana consumption, two years ago.  Other states and jurisdictions are following suit.  At the same time there have been attempts to move forward legislation all over the country variously to make guns as easy to purchase and carry as pot is in Colorado.  There is no public consumption of cannabis permitted in public in Colorado, or other jurisdictions, while conservative and libertarians have pushed for very liberal public display and to some degree more liberal use of firearms.
As a curious intersection of those two very different events, it is worth noting that one of the reasons given for the massacre death toll not being higher is that 4/20 was both a senior skip day, and a day when students cut class to go smoke pot.
From the Denver Post online:

The day is known in circles as "4-20'' - when students around the country skipped school to smoke marijuana. Aside from it having been April 20, the police code for a drug bust in Los Angeles is also 4-20.
"This is the big day for (smoking marijuana),'' said Columbine student Jason Greer, 16.

Anecdotal evidence suggests that both of the Columbine shooters were at least occasional pot smokers.

Did Eric & Dylan smoke weed? If so, was there proof?
Yes they did, and some friends and a coworker said they believed they did harder drugs too (but there’s no proof they actually did.) As for weed, there is proof. Witnesses say that they saw and/or joined them smoking weed in the smoker’s pit at school. On Eric’s survey, he said that his favorite thing to do on the weekend was “get stoned.” And, friends of theirs such as Chris Morris and Cory Friesen, said that they did indeed smoke weed. :)

Kliebold and Harris, the Columbine shooters and bombers, appear to have had a very easy time acquiring both illegal firearms through the assistance of straw purchasers, and illegal pot (also bomb-making components for 99 bombs).
Looking at the available statistics in Colorado, post-pot legalization, there seems to be far less problems resulting from legal, easily available marijuana than there have been from easily obtainable firearms, legal or otherwise.
Colorado initiated tough gun control laws, in part as a response to mass shootings, not only Columbine, but also more recently the Aurora theater shootings.  Typically (although not exclusively) it is conservatives, usually the more extreme conservatives, who seek out the most lax gun control laws, while at the same time more conservatives oppose legal marijuana.
As noted by Colorado kwgn channel 2:

DENVER — State lawmakers  are debating seven Republican bills that are all aimed at reversing and loosening gun restrictions in Colorado.

Sponsors of the bills admit most of the gun proposals will be hard to pass, many are looking at one bill in particular that would allow teachers to carry a concealed weapon.
Victims of mass shootings were at the Capitol Monday discussing if arming teachers will make a difference.
One of them was Jane Dougherty. Her sister was killed in the Newtown Elementary School shooting. She doesn’t think teachers should be armed. “I heard that over the last two-and-a-half years that if my sister had a gun, she could have shot the shooter. It`s a fantasy, like a blockbuster movie script.”
Lawmakers are also debating a bill that would let people carry concealed firearms without a permit.

So far, the experiment in Colorado of legalizing pot, regulating and taxing it, and making it easily accessible in a wide variety of forms has made a positive contribution to the state economy.  In sharp contrast is the cost of gun violence from too easily obtained firearms and lax gun control.  While estimates vary, depending on, for example, if one includes only direct costs, or also indirect costs, but the drain on society and the economy is substantial.
As noted in the Scholars Strategy Network Key Findings Report, "Worries about Safety, the Real Price of Gun Violence", by Philip J. Cook and Jens Ludwig, Sanford School, Duke University, August 2012 (the month following the Aurora Colorado mass shooting):

Estimating the costs of gun violence may imply a dry accounting exercise, toting up medical expenditures and earnings lost due to injury. Some research has been done this way, equating the cost with the burden on the health care system or losses to the labor force. But this misses the main point. For most people safety is the issue – and that is especially true for families with children. Gun violence in our vicinity –or just splayed all over our screens –undermines our sense of security and wellbeing at a visceral level. For neighborhoods where gun violence happens all the time, the threat is a reality of everyday life and has a profound effect on how

people live and feel. Avoidance and prevention take many forms, from costly security in schools and public buildings, to private decisions to commute many miles for the sake of living in a safe neighborhood, or (for those who do not have that choice) to keep the kids inside on summer evenings.
If gun violence affects people’s subjective feelings about security, how do we measure the effects? Arriving at specific dollar estimates is not easy, yet it can be done. Economists have used several methods to place a value on public safety. One method is to correlate property values to the objective risk of victimization. But my colleague Jens Ludwig and I used a more straightforward “contingent valuation” method, which hadoften been used in other domains, and especially to place a value on wilderness, clean air, and other aspects of environmental quality. This approach recognizes that the monetary value of surrounding conditions can be estimated by asking people how much they would pay to get improvements.

Referring to earlier research, contemporaneous with the Columbine High School mass shooting,  the  above cited research concludes:

Our research allowed us to estimate the total cost of gun violence, as people perceived it. As of 1998, the total cost to Americans was on the order of $80 billion (given that 30% of 80 is 24.5). We also discovered that the perceived high cost of gun violence is much more widespread than statistics about direct victims of gun attacks would suggest. Poor people are the ones who disproportionately experience gunshot injuries and deaths from direct assaults. But the threat of gun violence reduces the quality of life for a broad cross-section of Americans. Even those who live in relatively safe neighborhoods know that they and their children and friends are not entirely immune – as we are reminded by both the local newscasts and, all too frequently, the shooting rampages that make the national news. Cost estimates of this sort can help policymakers and voters consider the relative importance of reducing gun violence in comparison with all of the other social problems that compete for the attention of our towns, cities, states, and national government.Placing a dollar value on enhanced safety may seem a bit mechanistic, but it brings into focus the value of paying to enhance safety by fighting gun violence in comparison with paying to improve schools, health care, and housing. Based on our results, gun violence deserves a fairly prominent place on the agenda.

Colorado "got it"; the entire nation should "get it":  there are enormous benefits to being less restrictive with pot, and to being more restrictive with guns.  That holds true even after you subtract the huge investment in political influence by the NRA on behalf of the gun manufacturers for more guns guns guns.  More guns and more lax gun laws equal greater costs, both economic and social.  More pot in contrast seems to be beneficial both financially and socially, in contrast, if not without some minor problems similar to those with legal and regulated alcohol.