> Have nanotech magic-growth fences been invented and I didn't notice? Precisely how do you plan to do this? Oh I know, hire cheap Mexican labor? Or maybe bring over some Chinese to build the fences like we used them to build our railroads?

I do not have a problem with the rest of your post - but this statement isn't correct. A lot of countries have in the past successfully secured their borders. Even in lower technology times this was successfully done.