Let's assume President Trump will convince manufacturers to make their products in the USA, creating perhaps a million jobs or more. What then? There are many reasons that China and Mexico are ideal markets to manufacture. It's because they have very large local population pools of younger, under-educated people willing to labor for $3.49/hr as their turnkey workforce.
So where does one find this ideal setting in the USA? Germany provides an elaborate employee busing system to deliver their skilled workers to their auto plants in the rural countryside. Even if an ideal U.S. town/city existed with a large labor pool, U.S. demographics indicate a lack of younger low-wage skilled workers ready, willing and able to work in a factory setting for $12.50 an hour.
Then what about building the "wall"? This will cut off not only Mexican labor from entering the U.S., it will cut off the drug and money supply that fuels the infamous gangs of Chicago and other urban centers. What will they do, get real jobs? Doubtful, so does that mean more violent crime as a result of warfare for what remains of a drug supply? Likely.
Yep, these are things to consider beyond the shiny red ball in front of us, and ask "what if these plans do happen, then what?"