The USA needs to move trade from China to Mexico. The USA needs to work with their closer allies and increase the number of opportunities at the Mexican border to reduce illegal immigration, drugs, and human trafficking. The USA does not need to do this in spite of itself but instead to its own greater benefit.
The US spends billions keeping their borders protected from illegal immigration and plans to continue spending billions more. They break families up and crush dreams by deporting many people back to their homeland. Immigrants are desperate to find a new hope and to make their lives better and so they risk their lives to cross over into the USA. Many find out what opportunities lay within the USA and choose to stay even though they were required to go home. Who can blame them for wanting better?
The USA doesn't need to break up families and immigrants do not need to risk their lives to have a better future. Not at all. In fact the USA and Mexico can work together to make Mexico successful and plentiful. If good jobs and industry began to rise up within Mexico, Mexicans would not need to look any further than down the street for a good future. Currently Mexico is a great position to start becoming a great developing nation due to their low labor costs and location. The USA can ship parts and resources there by land and sea at a much cheaper and faster rate than they do to China making the assembly and production of the finished goods more efficient.
With such a large portion of the Americans having a Mexican heritage, the US is sure to be good allies with Mexico for some time. If the USA would work with Mexico they could strengthen a good neighbor and strong ally which could be essential in future war or strife. It could reduce the US's reliance on China and give the USA more leverage and stability in future trade and diplomacy across the ocean.
Why not put America First? Why not make America Great Again? The US can certainty achieve that and much more if they would just see the opportunities sitting right next door.
That is the why but how can the USA do this? Tariffs on China? That is the best part. It is already happening without a tariff but a tariff might help it along. As China continues to become more costly, Mexico becomes cheaper to do business with. The USA just needs to help Mexico prepare for the shift by making it known and advertising the benefits of doing business with Mexico. The USA also needs to help Mexico prepare for the many changes in their infrastructure. They will need more power, more roads, trains, and shipping terminals. The USA needs to be ready to supply that power and the materials for the roads and boats. So Spread the word and make America Great Again while making Mexico great too!