>>OTOH, every border is as penetrable as the counties it divides want. Every country has borders, they pretty much define it. The ratio between the border length and the population, i.e. how many miles of border per capita can't vary that much. In that respect, I figure Canada would fare the worst.
>>
>>So how come so many other countries don't have such problems?
>
>Because there isn't such a disparity in the standard of living.

Wasn't that alleviated by the NAFTA?