Trump might want to learn there is an agreement called NAFTA which prohibits import tariffs on the three countries in it.  Until he cancels it, US companies have the right to import goods for Mexico tariff free and even if he cancels it, only congress can apply tariffs and most Republicans are still pro free trade.  It was Ronald Reagan who brought free trade and many Republicans identify more with him than Trump.  This is another dumb idea from Trump who is economically illiterate.