I don't see any wrong in building wall between U.S. and Mexico. Because who will stop drugs and criminals coming from Mexico into U.S. ? A wall is to divide inside and outside. Of course word inside can be controlled from word outside. And word outside can be controlled from word inside. Pl.remember that present age is knowledge age which should take care self and other/s. Knowledge age is not building bridges with those people and country who are unable to control drugs and criminals from their side to enter other side. Isn't it so ?