If you go to Ohio, Upstate New York, Indiana, Pennsylvania, Michigan etc., you can see the empty factories-ghosts of the more prosperous times in American...before free trade, globalism, credit derivative crap etc...so yes Nafta did cause job losses....many job losses.
If you had any grasp of the subject you'd understand that government and the unions are responsible for those losses. Free trade and globalism (and credit derivatives?) are the last cries of blame from the union guys who got screwed by the people they trusted most: government and their union. When you trust others (government and unions) to look out for your well being, you'll get what you deserve.....unfortunately.