Getting some information straight helps do a more thorough analysis of the issue.
You need to back them up with some more specific hard facts and a couple of economic principles that apply to NAFTA. These facts and economic principles have the same implications for free trade in general.
1) What was the Unemployment Rate in 1992?
2) What was the Unemployment Rate in July 2000 and what is NARU?
3) What does the law of increasing opportunity cost say and what is its implications regarding steel and textile manufacturing and many other jobs that moved to Mexico and many other countries? What is the concept of creative destruction?
4) What does Aggregate Income = Aggregate Expenditures mean in the context of international trade?