I asked myself the same question the other day and found a document presented at the General Population Conference in 2001. It's titled "Why Borders Can Not Be

I asked myself the same question the other day and found a document presented at the General Population Conference in 2001. It's titled "Why Borders Can Not Be Open". I don't want to introduce any bias giving my thoughts about it, but I recommend you to read it your self: http://www.populationenvironmentresearch.org/papers/Colemanmigration.pdf http://www.populationenvironmentresearch.org/papers/Colemanm...