"Let em come, I hope they like the taste of blood in there water.
But seriously, there are lots of other solutions to water shortages, you can boil or evaporate sea water and then recolect it, it would sooner become economic (or at least combined with moral reasons) to build large filtering plants like that then go to war"
Can be done , and desalination is done in Israel ,but is expensive relative to getting water , as we do now, freely in the ground or surface. Even more expensive as it would come at a time where energy costs will be higher. A perfect storm of resource shortages and high population rates. One of the problems is overuse of underground aquifers, especially in very arid reagions....water there is like oil,,,once it's gone, its gone and its being used , rather friviously, irrigating water intensive crops in hot, dry climates (S US and Calif) where it is maily lost due to evap. Whatever happens in the US, I think the Great Lakes bordering states would be on the Canadian side.