Disclaimer: I'm a free trade kind of guy. I haven't read NAFTA. I certainly don't assume it is a free (fair) trade agreement just because it has "Free Trade Agreement" in the name (see Affordable Care Act).
A couple of years ago I looked around and I found a couple interesting historical graphs. One showed, IIRC, the US manufacturing jobs as a portion of global -- this showed a steady decline since WWII, with no spikes (for example, after 1994 when NAFTA was signed). The other showed US manufacturing output -- a steady increase over the same time. This made sense to me, we're becoming more productive while emerging markets are starting to emerge (so we produce more in terms of raw output, but less in terms of percent share of the increasing global output).
Tonight I found this chart (history of US manufacturing jobs) from the Bureau of Lying Statisticians:
What I see here is that the several years after NAFTA were the most stable in terms of US manufacturing jobs. Then, during two big economic busts we lost manufacturing jobs and didn't seem to get them back. Some will argue that since we didn't lose jobs as soon as the ink was dry then NAFTA was not a bad thing. Others will argue either that it took time for the (negative) effects of NAFTA to be felt, or that NAFTA is the reason jobs don't come back after a recession, as evidenced by the fact that the big drops happened after it was signed. Me? I don't know. Like I say, I haven't even read it.
The sharp decline at 2001 (9/11), more decline came while the EPA was slowly ramping up emissions standards during the Bush years, a sudden drop when the market crash happened in 2008, the slight increase during the Obama years might relate to one of the biggest Oil Booms the country has had since Spindletop. When it was done, North Dakota had gone from producing 150,000 BOPD to over 1 Million BOPD, with all the tubular goods, tools, new drilling rigs and modification packages to turn a basic rig into a walking rig for multi-well pads, and all the vehicles to handle all that from cars to Semis. Even so, a lot of Heavy Equipment was foreign made (lots of Kubota, and CAT was building in China) and a lot of parts were being made elsewhere. Tubular goods (drill pipe, casing) were coming from China, too, but the inferior durability and quality of the metallurgy soon had companies using American made tubulars again.
Overall, those jobs haven't recovered, and with the pressure to keep prices constant during the stagnant Obama Economy (Where people fell off the unemployment rolls instead of found work, and thus were not counted as unemployed) left people flooking for ways to improve their bottom line, and for the big boys, moving into new factories in a place where labor was cheaper was pretty seductive--so much so that that 'Great Sucking Sound' Mr. Perot talked about had reached the pitch of a jet at takeoff.
