Ashton asks “If Canada moves towards legalization of marijuana, how would that affect things, with alcohol prohibition as a template?”
First, some background. Canada, like the US, had its flirtation with prohibition, and in largely the same time period. During the late nineteenth and early twentieth century, areas in both countries banned alcohol, fueled in part by the women's temperance movement. Now, that seems like an odd thing for women to want, and I was confused in school until my teacher explained to me what was going on. Basically, a lot of men were working in factories, particularly when the Industrial Revolution got into full swing, and most of the time they had grueling, back-breaking 12-hour shifts; they relieved the stress and exhaustion by getting drunk off their asses in the neighborhood pubs and bars, followed by a great deal of domestic violence. Women figured that getting rid of alcohol would at least stop the drunken wife-beating, and many churches supported this—it probably would have been better to get factory owners to stop exploiting their workers so horribly, but I guess they didn't think that was in the cards yet.
Anyway, there was sort of a patchwork system of wet areas and dry areas across North America, until booze was banned entirely in the US in 1919, with the ratification of the 18th Amendment and passage of the Volstead Act; amusingly, Utah provided the 36th and last vote to ratify the 21st Amendment, ending the whole thing in 1933. So alcohol was illegal, with some exceptions, in the states, but more loosely regulated in Canada until 1918, though it was banned in Alberta and Ontario (and several provinces repealed it in the 20s). Smuggling quickly became a profitable sideline, and a haven for organized crime, considering that while many considered the demon rum to be immoral, quite a few also enjoyed a nice buzz now and then, or a glass of wine with dinner. In any case, prohibition likely reduced the use and sale of alcohol, but did not eliminate it by any stretch of the imagination, and also took the taxes that would have gone into government coffers and placed it into the pockets of the mob.
So that's more or less how Canada was involved in American prohibition. It seems quite likely that, were the trend towards drug liberalization to continue, Canada might well buck the USA's strict zero-tolerance policy towards marijuana, begun by Nixon, and allow the production of pot, whether for medicinal use only or permitting recreational farming as well, with the incentive of billions of dollars in taxes coming in. Many leaders in Central and South America, which face a good deal more drug production and violence than we do, have also expressed a desire to end the war on drugs, particularly since they see it as greatly empowering the cartels controlling much of the supply, who get most of their weapons from the US.
There might well be another smuggling trade, getting marijuana across the border, but unless Canada's shift in policy were accompanied by a pursuant laxity in our government, it would quite likely be harshly prosecuted, without the complicity in local police that was common in the twenties. Frankly, even if the sheriff of Watertown didn't have a problem with people smoking up now and then, the DEA might well just send in their own team anyway.
I suppose the root difference here is that alcohol has been with us for millennia; the Sumerians brewed beer, as did the Egyptians and Babylonians, and we're more or less accustomed to it being made and drunk; the prohibition movement only had any significant amount of strength in the late nineteenth and early twentieth centuries, and it barely exists now. Marijuana cultivation is quite a different story, and I daresay there's no one alive now who smoked it before it was effectively rendered illegal in 1937.
