The idea of borders to territories has been around since pre-history. Violation led to wars when it was a large amount. Small groups of visitors/travelers/trading people were allowed. The USA is invaded by 30 million, who are taking jobs Americans want, and taking benefits they never paid in for, and stated purposeful anti-environmental over-breeding with the goal of conquest the easy way (like the islamics in Europe have stated).
I joined the service to fight communism's spread for a small country that was too weak to fight the loss of freedom on its own. Communism is an enemy of freedom loving people, so is islam. Over-breeders are the enemy of the Earth.
The idea of one world all kumbaya is defeated by peoples who are in the above categories. It is also defeated by the fact that there is just too much variation in humans, especially in intelligence, and also in cultures and language.
