When NAFTA was signed, every voice of economic theory, every editorial page of every newspaper, every living ex president supported it. But it barely got through Congress.
Now, even the economists have to see what is in front of their eyes, that free trade does NOT benefit both parties. That the factors of production are indeed mobile. The ground has shifted out from under the free trade position. You are losing this debate both in academia and in the court of public opinion.
Of course the factors of production are mobile, and will stay that way. You'll get used to it. I haven't noticed the center of gravity of economists becoming protectionist. Perhaps I missed it.
NAFTA is why illegal immigration from Mexico has skyrocketed.
NAFTA allows American factory farms to sell freely to Mexico, which has put the Mexican farmers out of business because American produce is cheaper than Mexican.
So unemployed Mexican farmers must sneak into the U.S. to pick fruit or starve.