The US women and children gunned down horribly in Mexico were in Mexico and most of them have dual citizenship apparently. So nothing to do with the border, wall, etc.
But a lot to do with the Failed War on Drugs, which has transferred billions to criminals.
The US can't even manage or make the effort to fix/improve Mexico are neighbor with 130M people, or small central American countries. Yet the US believed it could transform Iraq, Afghanistan etc.
Much of the products we buy from China could easily be made in Mexico and South America, bringing them the same kind of boom that China has experienced. Wouldn't such a policy benefit the US on many levels, such as having stable neighbors, decreased immigration pressure as a result of a Hispanic America boom, drug issues would be mitigated, etc. Why funnel $300B a year to a communist competitor instead of allied neighbors.? US badly needs a geo-strategical trade policy.
For a supposedly sophisticated capitalist country, the US seems pretty stupid about where and to whom its money goes.