One can imagine future conflicts will be about all the above, rather like the competition between haves and have-nots within any given frame of reference.
Future conflicts will primarily arise from worldwide food scarcity in a cooling climate. Shorter growing seasons, and from unfriendly seasonal weather: too wet this year, too dry in another. Most Americans won't starve but competent resource management will be a must.
Look at food and energy availability in the coming decades.
--- "Look at food and energy availability in the coming decades."
Seems we are "on the same page" in this regard.
Supply and demand by those 'invisible hands', not government "allocation."
Which means Canada will be a bit of a basket case, until the Toronto-Ottawa "leaders" fail more obviously.