The world doesn't work with separate, contained nations. It never has and never will. It started with tribes, which roamed, and them discovered farming and claimed areas. Thus, nations were born. They were not alone. Others were born and had resources the others wanted. They got tired of war and decided to trade without killing. TA-DA: here we are. Believing that we could have the same lifestyle without other countries is ignorant. The simple fact that we do NOT have the amount of materials needed for our technology and the lack there of would jet us back fifty years with the rest of the world proves that. We have a lot of resources, but not all of them or enough of them.
Funny you should post the resources thing Lion. Was talking with the bro-in-law the other day about U.S. resources. He's a borderline isolationist, after we kick everybody's asses first that is. We have pretty much everything we need if push comes to shove. His thought is that by exploiting third world nation resources cheaply and with little environmental regard (Shell in Nigeria for example) we're landbanking our own for the day when global resources dwindle and prices skyrocket. Kinda makes sense in a twisted way.
See the rare-earth elements. It isn't going to destroy the world if we cant get enough of them, but we would have to do some serious retooling if we couldn't get those as easy as we do from foreign sources.
