Will Wilkinson of the Cato Institute asks this question and argues:
There are some who believe a grave threat to American sovereignty looms over the horizon. A shadowy cabal, they say, is planning a massive "NAFTA superhighway," a new North American currency, and a common market in goods and labor. It will all culminate in an E.U.-like North American Union.
It turns out this is mostly fantasy. But the fantasy is more dream than nightmare. Because some aspects of a North American Union would leave Americans and our neighbors both richer and freer.
The population of undocumented migrants in the U.S. has grown rapidly in recent decades -- in part because we have implemented increasingly restrictive border policies. What we've done is make passage riskier. This has slowed in-migration. But those who do come now are more likely to stay. And this has increased the permanent population of undocumented Mexicans.
The best solution to America's immigration problem is not a wall or a new crackdown on the hiring of undocumented workers. It's NAFTA's unfinished business: a common North American labor market. It's illogical and impractical to create a single North American economy that integrates markets for goods, capital, raw materials, services, and information but tries to keep labor markets divided.
Ron Paul is not going to like this.