This will bring more jobs back to the USA thus helping the American Worker get work again.
Mexico will lose even more industry...unless they decide to pay for the wall....and they may do the math and figure out that it is much cheaper to build a wall than to have even more of their people unemployed and unhappy and thus cause a revolution that throws those in power out.
People who are hoping manufacturing robots will help the problem are not figuring that this requires a lot of training that current lower income US workers may not get or be able to learn. People who think Trump’s charging a 20% import charge rather than charging a remittance export fee won’t hurt food costs are not thinking it through. We will not be expanding food production in US without the people willing to do stoop labor at what Mexicans work for here. In a town like Chincoteague, VA, stores hire girls from Russia and other lower income European places to work in the grocery stores because they can’t get the local labor.
Here is a link from a source you many not like, but there are a lot of pro Trump comments as well as one’s that just bring up potential wall building problems I have not heard here. One was, “where will we build the wall, in the middle of the river or on the US bank, thus ceding the entire river to Mexico,” and creating big problems for people using that water for cattle and agriculture.