As far as I know... NAFTA grew jobs and our economy. I will go ahead and look up info if necessary but I remember a lot of the myths being exploded.
I also have a buddy who is in the sugar business here as a grower. We have this discussion a lot. And he agrees he wouldnt support the government supporting other business' like for instance, Amtrak, airline bailouts, etc. But for some reason its ok to prop his industry?
Here is a Heritage Foundation take on it. I am assuming they did their homework.
http://www.heritage.org/Research/TradeandForeignAid/jtf5.cfm