Extremely simple answer. Mexico will lose $40-50 Billion trade surplus with US. With resulting loss of manufacturing jobs in Mexico, and transferring those jobs to US. Manufacturing is #1 wealth creator.
H.L. Menken once said that for every complex problem there is an answer that is clear, simple and wrong.
Mexico will lose $40-50 Billion trade surplus with US
Cut off trade with Mexico and we also lose all those jobs created by making the stuff we sent to them.
With resulting loss of manufacturing jobs in Mexico, and transferring those jobs to US. Manufacturing is #1 wealth creator.
More likely the jobs will remain there and the cost of the tariff will be passed on to U.S. consumers. Either way - manufacture there or manufacture here - the costs to U.S. consumers go up.