I'd say that it's a bit of both, but mostly NAFTA. And now CAFTA? Geez.
On a somewhat related note, it seems that many Americans are too lazy for much of the manual labor that we hire migrant workers to do. That doesn't help our job situation, either. Although if the business owners that depend on undocumented immigrant workforces paid more, they may have more Americans willing to work for them... I'm starting to really digress here, though. Sorry.
Here's the bit I find interesting:
A variation on the flat-tax idea, junking the income tax in favor of a single-rate national sales tax is also gaining popularity. "The Fair Tax," a new book by Rep. John Linder and radio talk-show host Neal Boortz, is currently topping best-seller lists.Done ethically (with no tax on essential food items), taxing via sales tax could be a viable solution. It might also encourage people to save money. And finally, the U.S. government would get their share of drug trade revenue and other black market trade. Sounds good to me.