[tptacek]

I'm guessing the climate has a lot to do with it, plus the huge amount of land you need to cultivate enough coca to produce cocaine (Canada having historically a stabler rule of law than Bolivia or Peru), plus the availability of extremely cheap (or, effectively, slave) labor for the cultivation.

If this begs the question "why is Canada more stable than Columbia, Peru, or Bolivia", apart from the fact that those are developing countries, it's worth remembering that the United States was aggressively and violently intervening in their politics into the middle of the 20th century. The same can't be said of The Maple Leaf States.