1. When we talk about narcoterrorism and "Mexico", we ought recall Prohibition: legalize, and the business goes away. The demand is from middle-class Americans: $ and numbers.
2. When we talk about immigration and legalization, keep in mind that widescale deportation or stigma means that there is no one to take care of children, landscape, pick fruit in the fields, etc.
3. When we talk about global warming, it is surely important to know the extent of the effect, and if possible information on whether it is called by societal actions (vs. some natural force). But you also need to then realize that any such physical consequence will surely lead to adaptations, some formal and statutory and by treaty, and many by price and market. If you have to talk about physics and about society.