If Donald Trump targets just Mexico and Congress agrees, other countries might think they were next and keep quiet.  Would others stand with Mexico and start a trade war or would they say NAFTA and trade is still OK and not much damage has been done to us so let's not rock the boat?  What could other countries do?  Would they apply tariffs, if none were initially applied to them?  Could you see South Koria, Japan or Germany retaliating because Mexico was being charged a toll?  Let's not use the same old rhetoric here and talking about World trade when we are talking only about the USA versus Mexico.