Realistically it will be a couple of years before NAFTA can be terminated - more complicated than the President simply declaring it dead.  When NAFTA does end, we will all feel it in many ways including the USA.  Many of their jobs will be lost due to the decreased exports but also, products that used to be made for $8/day in Mexico will now be made for $20/hour in the USA.  Let's see how President Trump's base likes the new prices.